Drillstring control framework

Abstract

A method may include acquiring magnetometer data using a downhole tool of a drillstring in a borehole, where the borehole includes at least one transition point between a cased portion of the borehole and an uncased portion of the borehole; selecting a number of techniques from a group of techniques implementable using downhole circuitry of the drillstring; applying the number of techniques to one or more portions of the magnetometer data to generate a corresponding number of results, where each of the results is indicative of a position of the downhole tool being within the cased portion or the uncased portion; and based on at least two of the results, controlling movement of the drillstring in the borehole.

Description

CROSS REFERENCE TO RELATED APPLICATIONS

[0001] This application claims priority to U.S. Provisional Patent Application No. 63 / 763,772, which was filed on Feb. 26, 2025, and is incorporated herein by reference in its entirety.BACKGROUND

[0002] A drillstring may be moved in a borehole for one or more purposes, which may pertain to tripping, drilling, etc. As an example, a borehole may include a transition between a cased portion and an uncased portion. In various instances, knowledge of where a drillstring is with respect to a cased portion, a transition, or an uncased portion may be relevant. For example, data acquired by one or more downhole tools may operate in a manner that may depend on whether or not a casing is present. As an example, various types of data may be relevant to steering a drillstring in a borehole, for example, for directional drilling that lengthens a borehole. As an example, consider geosteering, which may provide for directional control of a drill bit of a drillstring using downhole geological logging measurements, for example, to keep a directional wellbore within a pay zone. In various scenarios, control of a drillstring may be improved upon knowledge of a relationship of the drillstring, or a portion thereof, with respect to a cased portion, a transition point, or an uncased portion of a borehole.SUMMARY

[0003] A method may include acquiring magnetometer data using a downhole tool of a drillstring in a borehole, where the borehole includes at least one transition point between a cased portion of the borehole and an uncased portion of the borehole; selecting a number of techniques from a group of techniques implementable using downhole circuitry of the drillstring; applying the number of techniques to one or more portions of the magnetometer data to generate a corresponding number of results, where each of the results is indicative of a position of the downhole tool being within the cased portion or the uncased portion; and based on at least two of the results, controlling movement of the drillstring in the borehole. A system can include a processor; memory accessible to the processor; and processor-executable instructions stored in the memory and executable by the processor to instruct the system to: acquire magnetometer data using a downhole tool of a drillstring in a borehole, where the borehole includes at least one transition point between a cased portion of the borehole and an uncased portion of the borehole; select a number of techniques from a group of techniques implementable using downhole circuitry of the drillstring; apply the number of techniques to one or more portions of the magnetometer data to generate a corresponding number of results, where each of the results is indicative of a position of the downhole tool being within the cased portion or the uncased portion; and, based on at least two of the results, control movement of the drillstring in the borehole. One or more non-transitory computer-readable storage media may include processor-executable instructions executable to instruct a processor to: acquire magnetometer data using a downhole tool of a drillstring in a borehole, where the borehole includes at least one transition point between a cased portion of the borehole and an uncased portion of the borehole; select a number of techniques from a group of techniques implementable using downhole circuitry of the drillstring; apply the number of techniques to one or more portions of the magnetometer data to generate a corresponding number of results, where each of the results is indicative of a position of the downhole tool being within the cased portion or the uncased portion; and, based on at least two of the results, control movement of the drillstring in the borehole. Various other apparatuses, systems, methods, etc., are also disclosed.

[0004] This summary is provided to introduce a selection of concepts that are further described below in the detailed description. This summary is not intended to identify key or essential features of the claimed subject matter, nor is it intended to be used as an aid in limiting the scope of the claimed subject matter.BRIEF DESCRIPTION OF THE DRAWINGS

[0005] Features and advantages of the described implementations may be more readily understood by reference to the following description taken in conjunction with the accompanying drawings.

[0006] FIG. 1 illustrates examples of equipment in a geologic environment;

[0007] FIG. 2 illustrates an example of a system and examples of types of holes;

[0008] FIG. 3 illustrates an example of a geologic environment with a borehole and an example of a portion of a drillstring that may include various components;

[0009] FIG. 4 illustrates an example of a portion of a drillstring that may include various components;

[0010] FIG. 5 illustrates examples of logs;

[0011] FIG. 6 illustrates an example of a workflow;

[0012] FIG. 7 illustrates an example of a system;

[0013] FIG. 8 illustrates an example of a plot;

[0014] FIG. 9 illustrates examples of plots;

[0015] FIG. 10 illustrates examples of plots;

[0016] FIG. 11 illustrates an example of a method and an example of a system; and

[0017] FIG. 12 illustrates examples of computing and networking equipment.DETAILED DESCRIPTION

[0018] The following description includes embodiments of the best mode presently contemplated for practicing the described implementations. This description is not to be taken in a limiting sense, but rather is made merely for the purpose of describing the general principles of the implementations. The scope of the described implementations should be ascertained with reference to the issued claims.

[0019] A borehole may be referred to as a wellbore and may include an openhole portion or an uncased portion and / or may include a cased portion. As explained, a borehole may include a transition point between a cased portion and an uncased portion. In various instances, a borehole may include one or more cased portions and one or more uncased portions. As an example, a borehole may be defined by a bore wall that is composed of rock that bounds the borehole, noting that casing may be disposed in a borehole where the casing may act as a fluid barrier and / or as a stabilizer. As an example, a portion of casing may include one or more penetrations such that, for example, fluid may move from a formation to a borehole or from a borehole to a formation.

[0020] As an example, casing may be metallic. For example, casing may be manufactured from carbon steel that is heat-treated to varying strengths. In various instances, casing may be made of one or more of stainless steel, aluminum, titanium, fiberglass, and one or more other materials. Where casing includes a metal or metals, it may be referred to as metallic casing. As an example, various types of metals may be ferromagnetic or otherwise interact with or interfere with a magnetic field. In various instances, movement of a metallic component, a magnetometer, fluid, etc., may impact a magnetic field. For example, consider movement of aluminum in the presence of a magnetic field whereby the aluminum may generate eddy currents, which may oppose the magnetic field.

[0021] In various instances, casing may be set using cement where cement may be disposed between an outer surface of the casing and bore wall, as may be formed of rock. As an example, cementing may involve preparing and pumping cement into place in borehole. Cementing operations may be undertaken, for example, to seal an annulus after a casing string has been run, to seal a lost circulation zone, to set a plug in an existing well from which to push off with directional tools or to plug a well so that it may be abandoned, etc.

[0022] In various instances, drilling may occur in stages or sections where, for example, a drilled section may be at least in part cased prior to drilling another section. Setting casing, cementing, etc., may be part of one or more completions operations. Completions operations generally provide for preparation of a borehole to function as a completed well. Completions may refer to an assembly of downhole tubulars and equipment that aim to enable safe and efficient production and / or injection of fluid.

[0023] As to a well or a borehole, whether for one or more of exploration, sensing, production, injection or other operation(s), it may be planned. Such a process may be referred to generally as well planning, a process by which a path may be mapped in a geologic environment. Such a path may be referred to as a trajectory, which may include coordinates in a three-dimensional coordinate system where a measure along the trajectory may be a measured depth (MD), a total vertical depth (TVD) or another type of measure.

[0024] As an example, drilling may include using one or more logging tools that may perform one or more logging operations while drilling or otherwise with a drillstring (e.g., while stationary, while tripping in, tripping out, etc.). As an example, drilling or one or more other operations may occur responsive to measurements. For example, a logging while drilling operation may acquire measurements and adjust drilling based at least in part on such measurements. In such an example, adjustments may be made by actuating one or more steering actuators that may provide for orienting a drill bit of a drillstring. As an example, one or more types of measurements may be relevant to control of movement of a drillstring in a borehole, for example, as to drilling, hydrodynamics, positioning, etc.

[0025] FIG. 1 shows an example of a system 100 that includes a workspace framework 110 that may provide for instantiation of, rendering of, interactions with, etc., a graphical user interface (GUI) 120. In the example of FIG. 1, the GUI 120 may include graphical controls for computational frameworks (e.g., applications, etc.) 121, projects 122, visualization features 123, one or more other features 124, data access 125, and data storage 126.

[0026] In the example of FIG. 1, the workspace framework 110 may be tailored to a particular geologic environment such as an example geologic environment 150. For example, the geologic environment 150 may include layers (e.g., stratification) that include a reservoir 151 and that may be intersected by a fault 153. As an example, the geologic environment 150 may be outfitted with a variety of sensors, detectors, actuators, etc. For example, equipment 152 may include communication circuitry to receive and to transmit information with respect to one or more networks 155. Such information may include information associated with downhole equipment 154, which may be equipment to acquire information, to assist with resource recovery, etc. Other equipment 156 may be located remote from a wellsite and include sensing, detecting, emitting or other circuitry. Such equipment may include storage and communication circuitry to store and to communicate data, instructions, etc. As an example, one or more satellites may be provided for purposes of communications, data acquisition, etc. For example, FIG. 1 shows a satellite 170 in communication with the network 155 that may be configured for communications, noting that the satellite may additionally or alternatively include circuitry for imagery (e.g., spatial, spectral, temporal, radiometric, etc.).

[0027] FIG. 1 also shows the geologic environment 150 as optionally including equipment 157 and 158 associated with a well that includes a substantially horizontal portion that may intersect with one or more fractures 159. For example, consider a well in a shale formation that may include natural fractures, artificial fractures (e.g., hydraulic fractures) or a combination of natural and artificial fractures. As an example, a well may be drilled for a reservoir that is laterally extensive. In such an example, lateral variations in properties, stresses, etc. may exist where an assessment of such variations may assist with planning, operations, etc. to develop a laterally extensive reservoir (e.g., via fracturing, injecting, extracting, etc.). As an example, the equipment 157 and / or 158 may include components, a system, systems, etc. for fracturing, seismic sensing, analysis of seismic data, assessment of one or more fractures, etc.

[0028] In the example of FIG. 1, the GUI 120 shows some examples of computational frameworks, including the DRILLPLAN, DRILLOPS, PETREL, TECHLOG, PETROMOD, ECLIPSE, PIPESIM, and INTERSECT frameworks (SLB, Houston, Texas).

[0029] The DRILLPLAN framework provides for digital well construction planning and includes features for automation of repetitive tasks and validation workflows, enabling improved quality drilling programs (e.g., digital drilling plans, etc.) to be produced quickly with assured coherency.

[0030] The DRILLOPS framework may execute a digital drilling plan and ensures plan adherence, while delivering goal-based automation. The DRILLOPS framework may generate activity plans automatically individual operations, whether they are monitored and / or controlled on the rig or in town. Automation may utilize data analysis and learning systems to assist and optimize tasks, such as, for example, setting ROP to drilling a stand. A preset menu of automatable drilling tasks may be rendered, and, using data analysis and models, a plan may be executed in a manner to achieve a specified goal, where, for example, measurements may be utilized for calibration. The DRILLOPS framework provides flexibility to modify and replan activities dynamically, for example, based on a live appraisal of various factors (e.g., equipment, personnel, and supplies). Well construction activities (e.g., tripping, drilling, cementing, etc.) may be continually monitored and dynamically updated using feedback from operational activities. The DRILLOPS framework may provide for various levels of automation based on planning and / or re-planning (e.g., via the DRILLPLAN framework), feedback, etc.

[0031] The PETREL framework may be part of the DELFI environment for utilization in geosciences and geoengineering, for example, to analyze subsurface data from exploration to production of fluid from a reservoir. The DELFI cognitive exploration and production (E&P) environment (SLB, Houston, Texas), referred to herein as the DELFI environment or DELFI framework, is a secure, cognitive, cloud-based collaborative environment that integrates data and workflows with digital technologies, such as artificial intelligence and machine learning.

[0032] The PETREL framework provides components that allow for optimization of various exploration, development and production operations. The PETREL framework includes seismic to simulation software components that may output information for use in increasing reservoir performance, for example, by improving asset team productivity. Through use of such a framework, various professionals (e.g., geophysicists, geologists, and reservoir engineers) may develop collaborative workflows and integrate operations to streamline processes (e.g., with respect to one or more geologic environments, etc.). Such a framework may be considered an application (e.g., executable using one or more devices) and may be considered a data-driven application (e.g., where data is input for purposes of modeling, simulating, etc.).

[0033] The TECHLOG framework may handle and process field and laboratory data for a variety of geologic environments (e.g., deepwater exploration, shale, etc.). The TECHLOG framework may structure wellbore data for analyses, planning, etc.

[0034] The PETROMOD framework provides petroleum systems modeling capabilities that may combine one or more of seismic, well, and geological information to model the evolution of a sedimentary basin. The PETROMOD framework may predict if, and how, a reservoir has been charged with hydrocarbons, including the source and timing of hydrocarbon generation, migration routes, quantities, and hydrocarbon type in the subsurface or at surface conditions.

[0035] The ECLIPSE framework provides a reservoir simulator (e.g., as a computational framework) with numerical solutions for fast and accurate prediction of dynamic behavior for various types of reservoirs and development schemes.

[0036] The INTERSECT framework provides a high-resolution reservoir simulator for simulation of detailed geological features and quantification of uncertainties, for example, by creating accurate production scenarios and, with the integration of precise models of the surface facilities and field operations, the INTERSECT framework may produce reliable results, which may be continuously updated by real-time data exchanges (e.g., from one or more types of data acquisition equipment in the field that may acquire data during one or more types of field operations, etc.). The INTERSECT framework may provide completion configurations for complex wells where such configurations may be built in the field, may provide detailed enhanced-oil-recovery (EOR) formulations where such formulations may be implemented in the field, may analyze application of steam injection and other thermal EOR techniques for implementation in the field, advanced production controls in terms of reservoir coupling and flexible field management, and flexibility to script customized solutions for improved modeling and field management control. The INTERSECT framework, as with the other example frameworks, may be utilized as part of the DELFI environment, for example, for rapid simulation of multiple concurrent cases. For example, a workflow may utilize one or more of the DELFI environment on demand reservoir simulation features.

[0037] The aforementioned DELFI environment provides various features for workflows as to subsurface analysis, planning, construction and production, for example, as illustrated in the workspace framework 110. As shown in FIG. 1, outputs from the workspace framework 110 may be utilized for directing, controlling, etc., one or more processes in the geologic environment 150 and, feedback 160, may be received via one or more interfaces in one or more forms (e.g., acquired data as to operational conditions, equipment conditions, environment conditions, etc.).

[0038] As an example, a workflow may progress to a geology and geophysics (“G&G”) service provider, which may generate a well trajectory, which may involve execution of one or more G&G frameworks (e.g., consider the PETREL framework, etc.).

[0039] In the example of FIG. 1, the visualization features 123 may be implemented via the workspace framework 110, for example, to perform tasks as associated with one or more of subsurface regions, planning operations, constructing wells and / or surface fluid networks, and producing from a reservoir.

[0040] As an example, a visualization process may implement one or more of various features that may be suitable for one or more web applications. For example, a template may involve use of the JAVASCRIPT object notation format (JSON) and / or one or more other languages / formats. As an example, a framework may include one or more converters. For example, consider a JSON to PYTHON converter and / or a PYTHON to JSON converter. Such an approach may provide for compatibility of devices, frameworks, etc., with respect to one or more sets of instructions.

[0041] As an example, visualization features may provide for visualization of various earth models, properties, etc., in one or more dimensions. As an example, visualization features may provide for rendering of information in multiple dimensions, which may optionally include multiple resolution rendering. In such an example, information being rendered may be associated with one or more frameworks and / or one or more data stores. As an example, visualization features may include one or more control features for control of equipment, which may include, for example, field equipment that may perform one or more field operations. As an example, a workflow may utilize one or more frameworks to generate information that may be utilized to control one or more types of field equipment (e.g., drilling equipment, wireline equipment, fracturing equipment, etc.).

[0042] As to a reservoir model that may be suitable for utilization by a simulator, consider acquisition of seismic data as acquired via reflection seismology, which finds use in geophysics, for example, to estimate properties of subsurface formations. As an example, reflection seismology may provide seismic data representing waves of elastic energy (e.g., as transmitted by P-waves and S-waves, in a frequency range of approximately 1 Hz to approximately 100 Hz). Seismic data may be processed and interpreted, for example, to understand better composition, fluid content, extent and geometry of subsurface rocks. Such interpretation results may be utilized to plan, simulate, perform, etc., one or more operations for production of fluid from a reservoir (e.g., reservoir rock, etc.).

[0043] As an example, a model may be a simulated version of a geologic environment. As an example, a simulator may include features for simulating physical phenomena in a geologic environment based at least in part on a model or models. A simulator, such as a reservoir simulator, may simulate fluid flow in a geologic environment based at least in part on a model that may be generated via a framework that receives seismic data. A simulator may be a computerized system (e.g., a computing system) that may execute instructions using one or more processors to solve a system of equations that describe physical phenomena subject to various constraints. In such an example, the system of equations may be spatially defined (e.g., numerically discretized) according to a spatial model that that includes layers of rock, geobodies, etc., that have corresponding positions that may be based on interpretation of seismic and / or other data. A spatial model may be a cell-based model where cells are defined by a grid (e.g., a mesh). A cell in a cell-based model may represent a physical area or volume in a geologic environment where the cell may be assigned physical properties (e.g., permeability, fluid properties, etc.) that may be germane to one or more physical phenomena (e.g., fluid volume, fluid flow, pressure, etc.). A reservoir simulation model may be a spatial model that may be cell-based.

[0044] While several simulators are illustrated in the example of FIG. 1, one or more other simulators may be utilized, additionally or alternatively. For example, consider the VISAGE geomechanics simulator (SLB, Houston Texas) or the PIPESIM network simulator (SLB, Houston Texas), etc.

[0045] As an example, a workflow may utilize one or more types of data for one or more processes (e.g., stratigraphic modeling, basin modeling, completion designs, drilling, production, injection, etc.). As an example, one or more tools may provide data that may be used in a workflow or workflows that may implement one or more frameworks (e.g., PETREL, TECHLOG, PETROMOD, ECLIPSE, etc.).

[0046] In the example of FIG. 1, drilling may be performed in the geologic environment 150, for example, to access the reservoir 151, which may be accessed from land or offshore. In FIG. 1, the downhole equipment 154 may be, for example, part of a bottom hole assembly (BHA). The BHA may be used to drill a well. The downhole equipment 154 may communicate information to equipment at the surface, and may receive instructions and information from the equipment at the surface. During a well construction process, a variety of operations (such as cementing, wireline evaluation, testing, etc.) may be conducted. In such embodiments, data collected by tools and sensors and used for reasons such as reservoir characterization may be collected and transmitted.

[0047] A well may include a substantially horizontal portion (e.g., lateral portion) that may intersect with one or more fractures. For example, a well in a shale formation may pass through natural fractures, artificial fractures (e.g., hydraulic fractures), or a combination thereof. Such a well may be constructed using directional drilling techniques as described herein. However, these same techniques may be used in connection with other types of directional wells (such as slant wells, S-shaped wells, deep inclined wells, and others) and are not limited to horizontal wells.

[0048] As an example, a platform, such as, for example, the LUMI platform (SLB, Houston, Texas) may be utilized. The LUMI platform includes features that provide for artificial intelligence solutions as may be integrated with data management capabilities. The LUMI platform provides for flexible deployment options and an open, secure, and modular architecture, for example, to empower data-driven decision-making. The LUMI platform is operable with the DELFI environment and, hence, one or more of various frameworks. While various platforms, environments, frameworks, libraries, etc., are mentioned, a framework may be operable in an agnostic manner, for example, to be compatible with one or more other platforms, environments, frameworks, libraries, technologies, etc.

[0049] FIG. 2 shows an example of a wellsite system 200 (e.g., at a wellsite that may be onshore or offshore). As shown, the wellsite system 200 may include a mud tank 201 for holding mud and other material (e.g., where mud may be a drilling fluid that may help to transport cuttings, etc.), a suction line 203 that serves as an inlet to a mud pump 204 for pumping mud from the mud tank 201 such that mud flows to a vibrating hose 206, a drawworks 207 for winching drill line or drill lines 212, a standpipe 208 that receives mud from the vibrating hose 206, a kelly hose 209 that receives mud from the standpipe 208, a gooseneck or goosenecks 210, a traveling block 211, a crown block 213 for carrying the traveling block 211 via the drill line or drill lines 212 (see, e.g., the crown block 173 of FIG. 1), a derrick 214 (see, e.g., the derrick 172 of FIG. 1), a kelly 218 or a top drive 240, a kelly drive bushing 219, a rotary table 220, a drill floor 221, a bell nipple 222, one or more blowout preventors (BOPs) 223, a drillstring 225, a drill bit 226, a casing head 227 and a flow pipe 228 that carries mud and other material to, for example, the mud tank 201.

[0050] In the example system of FIG. 2, a borehole 232 is formed in subsurface formations 230 by rotary drilling; noting that various example embodiments may also use directional drilling or one or more other types of drilling.

[0051] As shown in the example of FIG. 2, the drillstring 225 is suspended within the borehole 232 and has a drillstring assembly 250 that includes the drill bit 226 at its lower end. As an example, the drillstring assembly 250 may be a bottom hole assembly (BHA).

[0052] The wellsite system 200 may provide for operation of the drillstring 225 and other operations. As shown, the wellsite system 200 includes the platform 215 and the derrick 214 positioned over the borehole 232. As mentioned, the wellsite system 200 may include the rotary table 220 where the drillstring 225 passes through an opening in the rotary table 220.

[0053] As shown in the example of FIG. 2, the wellsite system 200 may include the kelly 218 and associated components, etc., or a top drive 240 and associated components. As to a kelly example, the kelly 218 may be a square or hexagonal metal / alloy bar with a hole drilled therein that serves as a mud flow path. The kelly 218 may be used to transmit rotary motion from the rotary table 220 via the kelly drive bushing 219 to the drillstring 225, while allowing the drillstring 225 to be lowered or raised during rotation. The kelly 218 may pass through the kelly drive bushing 219, which may be driven by the rotary table 220. As an example, the rotary table 220 may include a master bushing that operatively couples to the kelly drive bushing 219 such that rotation of the rotary table 220 may turn the kelly drive bushing 219 and hence the kelly 218. The kelly drive bushing 219 may include an inside profile matching an outside profile (e.g., square, hexagonal, etc.) of the kelly 218; however, with slightly larger dimensions so that the kelly 218 may freely move up and down inside the kelly drive bushing 219.

[0054] As to a top drive example, the top drive 240 may provide functions performed by a kelly and a rotary table. The top drive 240 may turn the drillstring 225. As an example, the top drive 240 may include one or more motors (e.g., electric and / or hydraulic) connected with appropriate gearing to a short section of pipe called a quill, that in turn may be screwed into a saver sub or the drillstring 225 itself. The top drive 240 may be suspended from the traveling block 211, so the rotary mechanism is free to travel up and down the derrick 214. As an example, a top drive 240 may allow for drilling to be performed with more joint stands than a kelly / rotary table approach.

[0055] In the example of FIG. 2, the mud tank 201 may hold mud, which may be one or more types of drilling fluids. As an example, a wellbore may be drilled to produce fluid, inject fluid or both (e.g., hydrocarbons, minerals, water, etc.).

[0056] In the example of FIG. 2, the drillstring 225 (e.g., including one or more downhole tools) may be composed of a series of pipes threadably connected together to form a long tube with the drill bit 226 at the lower end thereof. As the drillstring 225 is advanced into a wellbore for drilling, at some point in time prior to or coincident with drilling, the mud may be pumped by the pump 204 from the mud tank 201 (e.g., or other source) via the lines 206, 208 and 209 to a port of the kelly 218 or, for example, to a port of the top drive 240. The mud may then flow via a passage (e.g., or passages) in the drillstring 225 and out of ports located on the drill bit 226 (see, e.g., a directional arrow). As the mud exits the drillstring 225 via ports in the drill bit 226, it may then circulate upwardly through an annular region between an outer surface(s) of the drillstring 225 and surrounding wall(s) (e.g., open borehole, casing, etc.), as indicated by directional arrows. In such a manner, the mud lubricates the drill bit 226 and carries heat energy (e.g., frictional or other energy) and formation cuttings to the surface where the mud (e.g., and cuttings) may be returned to the mud tank 201, for example, for recirculation (e.g., with processing to remove cuttings, etc.).

[0057] The mud pumped by the pump 204 into the drillstring 225 may, after exiting the drillstring 225, form a mudcake that lines the wellbore which, among other functions, may reduce friction between the drillstring 225 and surrounding wall(s) (e.g., borehole, casing, etc.). A reduction in friction may facilitate advancing or retracting the drillstring 225. During a drilling operation, the entire drillstring 225 may be pulled from a wellbore and optionally replaced, for example, with a new or sharpened drill bit, a smaller diameter drillstring, etc. As mentioned, the act of pulling a drillstring out of a hole or replacing it in a hole is referred to as tripping. A trip may be referred to as an upward trip or an outward trip or as a downward trip or an inward trip depending on trip direction.

[0058] As an example, consider a downward trip where upon arrival of the drill bit 226 of the drillstring 225 at a bottom of a wellbore, pumping of the mud commences to lubricate the drill bit 226 for purposes of drilling to enlarge the wellbore. As mentioned, the mud may be pumped by the pump 204 into a passage of the drillstring 225 and, upon filling of the passage, the mud may be used as a transmission medium to transmit energy, for example, energy that may encode information as in mud-pulse telemetry.

[0059] As an example, mud-pulse telemetry equipment may include a downhole device configured to effect changes in pressure in the mud to create an acoustic wave or waves upon which information may modulated. In such an example, information from downhole equipment (e.g., one or more components of the drillstring 225) may be transmitted uphole to an uphole device, which may relay such information to other equipment for processing, control, etc.

[0060] As an example, telemetry equipment may operate via transmission of energy via the drillstring 225 itself. For example, consider a signal generator that imparts coded energy signals to the drillstring 225 and repeaters that may receive such energy and repeat it to further transmit the coded energy signals (e.g., information, etc.).

[0061] As an example, the drillstring 225 may be fitted with telemetry equipment 252 that includes a rotatable drive shaft, a turbine impeller mechanically coupled to the drive shaft such that the mud may cause the turbine impeller to rotate, a modulator rotor mechanically coupled to the drive shaft such that rotation of the turbine impeller causes said modulator rotor to rotate, a modulator stator mounted adjacent to or proximate to the modulator rotor such that rotation of the modulator rotor relative to the modulator stator creates pressure pulses in the mud, and a controllable brake for selectively braking rotation of the modulator rotor to modulate pressure pulses. In such example, an alternator may be coupled to the aforementioned drive shaft where the alternator includes at least one stator winding electrically coupled to a control circuit to selectively short the at least one stator winding to electromagnetically brake the alternator and thereby selectively brake rotation of the modulator rotor to modulate the pressure pulses in the mud.

[0062] In the example of FIG. 2, an uphole control and / or data acquisition system 262 may include circuitry to sense pressure pulses generated by telemetry equipment 252 and, for example, communicate sensed pressure pulses or information derived therefrom for process, control, etc.

[0063] The assembly 250 of the illustrated example includes a logging-while-drilling (LWD) module 254, a measurement-while-drilling (MWD) module 256, an optional module 258, a rotary-steerable system (RSS) and / or motor 260, and the drill bit 226. Such components or modules may be referred to as tools where a drillstring may include a plurality of tools.

[0064] As to an RSS, it involves technology utilized for direction drilling. Directional drilling involves drilling into the Earth to form a deviated bore such that the trajectory of the bore is not vertical; rather, the trajectory deviates from vertical along one or more portions of the bore. As an example, consider a target that is located at a lateral distance from a surface location where a rig may be stationed. In such an example, drilling may commence with a vertical portion and then deviate from vertical such that the bore is aimed at the target and, eventually, reaches the target. Directional drilling may be implemented where a target may be inaccessible from a vertical location at the surface of the Earth, where material exists in the Earth that may impede drilling or otherwise be detrimental (e.g., consider a salt dome, etc.), where a formation is laterally extensive (e.g., consider a relatively thin yet laterally extensive reservoir), where multiple bores are to be drilled from a single surface bore, where a relief well is desired, etc.

[0065] One approach to directional drilling involves a mud motor; noting that a mud motor may present some challenges depending on factors such as rate of penetration (ROP), transferring weight to a bit (e.g., weight on bit, WOB) due to friction, etc. A mud motor may be a positive displacement motor (PDM) that operates to drive a bit during directional drilling. A PDM operates as drilling fluid is pumped through it where the PDM converts hydraulic power of the drilling fluid into mechanical power to cause the bit to rotate. A PDM may operate in a so-called sliding mode, when the drillstring is not rotated from the surface.

[0066] An RSS may drill directionally where there is continuous rotation from surface equipment, which may alleviate the sliding of a steerable motor (e.g., a PDM). An RSS may be deployed when drilling directionally (e.g., deviated, horizontal, or extended-reach wells). An RSS may aim to minimize interaction with a borehole wall, which may help to preserve borehole quality. An RSS may aim to exert a relatively consistent side force akin to stabilizers that rotate with the drillstring or orient the bit in the desired direction while continuously rotating at the same number of rotations per minute as the drillstring.

[0067] The LWD module 254 may be housed in a suitable type of drill collar and may contain one or a plurality of selected types of logging tools (e.g., NMR unit or units, etc.). It will also be understood that one or more LWD and / or MWD modules may be employed at one or more positions. An LWD module may include capabilities for measuring, processing, and storing information, as well as for communicating with the surface equipment. In the illustrated example, the LWD module 254 may include a seismic measuring device (e.g., sonic, etc.), an NMR measuring device, a resistivity measuring device, etc.

[0068] The MWD module 256 may be housed in a suitable type of drill collar and may contain one or more devices for measuring characteristics of the drillstring 225 and the drill bit 226. As an example, the MWD module 256 may include equipment for generating electrical power, for example, to power various components of the drillstring 225. As an example, the MWD module 256 may include the telemetry equipment 252, for example, where the turbine impeller may generate power by flow of the mud; it being understood that other power and / or battery systems may be employed for purposes of powering various components. As an example, the MWD module 256 may include one or more of the following types of measuring devices: a weight-on-bit measuring device, a torque measuring device, a vibration measuring device, a shock measuring device, a stick slip measuring device, a direction measuring device, and an inclination measuring device.

[0069] As an example, one or more measuring devices may be included in a drillstring (e.g., a BHA, etc.) where, for example, measurements may support one or more of geosteering, geostopping, trajectory optimization, etc.

[0070] FIG. 2 also shows some examples of types of holes that may be drilled. For example, consider a slant hole 272, an S-shaped hole 274, a deep inclined hole 276 and a horizontal hole 278.

[0071] As an example, a drilling operation may include directional drilling where, for example, at least a portion of a well includes a curved axis. For example, consider a radius that defines curvature where an inclination with regard to the vertical may vary until reaching an angle between about 30 degrees and about 60 degrees or, for example, an angle to about 90 degrees or possibly greater than about 90 degrees. As an example, a trajectory and / or a drillstring may be characterized in part by a dogleg severity (DLS), which may be a two-dimensional parameter specified in degrees per 30 meters (e.g., or degrees per 100 feet).

[0072] As an example, a directional well may include several shapes where each of the shapes may aim to meet particular operational demands. As an example, a drilling process may be performed on the basis of information as and when it is relayed to a drilling engineer. As an example, inclination and / or direction may be modified based on information received during a drilling process.

[0073] As an example, deviation of a bore may be accomplished in part by use of a downhole motor and / or a turbine. As to a motor, consider a drillstring that may include a positive displacement motor (PDM).

[0074] As an example, a system may be a steerable system and include equipment to perform a method such as geosteering. As mentioned, a steerable system may be or include an RSS. As an example, a steerable system may include a PDM and / or a turbine on a lower part of a drillstring which, just above a drill bit, a bent sub may be mounted. Geosteering equipment of a drillstring may include one or more geosteering actuators that may provide for orienting a drill bit of the drillstring. For example, an actuator that may include a piston that moves a pad for providing a force that may be exerted against a borehole wall thus steering a bottom hole assembly (e.g., orienting a drill bit of the bottom hole assembly). As an example, an actuator may be a bent downhole motor, which may be actuated via one or more processes. As an example, a bent drilling motor may be used with a fixed bend that cannot be varied during normal operation or with a variable bend that, for example, may be varied based on a geosteering command. As an example, for a variable bend drilling motor, one or more actuators may be included that may be configured to create or vary a bend, thereby affecting the steering behavior of the steering system. As an example, an actuator may be a downhole actuator that may adjust orientation downhole and / or an actuator may be a surface actuator that may perform an action uphole (e.g., at surface) to adjust orientation downhole.

[0075] As an example, above a PDM, MWD equipment that provides real time or near real time data of interest (e.g., inclination, direction, pressure, temperature, real weight on the drill bit, torque stress, etc.) and / or LWD equipment may be installed. As to the latter, LWD equipment may make it possible to send to the surface various types of data of interest, including for example, geological data (e.g., gamma ray log, resistivity, density and sonic logs, etc.).

[0076] The coupling of sensors providing information on the course of a well trajectory, in real time or near real time, with, for example, one or more logs characterizing the formations from a geological viewpoint, may allow for implementing a geosteering method. Such a method may include navigating a subsurface environment, for example, to follow a desired route to reach a desired target or targets.

[0077] As an example, a drillstring may include one or more of an azimuthal density neutron (ADN) tool for measuring density and porosity; a MWD tool for measuring inclination, azimuth and shocks; a compensated dual resistivity (CDR) tool for measuring resistivity and gamma ray related phenomena; a combinable magnetic resonance (CMR) tool for measuring properties (e.g., relaxation properties, etc.); one or more variable gauge stabilizers; one or more bend joints; and a geosteering tool, which may include a motor and optionally equipment for measuring and / or responding to one or more of inclination, resistivity and gamma ray related phenomena.

[0078] As an example, a tool such as the ECOSCOPE tool (SLB, Houston, Texas) may be utilized to acquire measurements. Such a tool may include one or more PNGs and associated detectors. Such a tool may include features for one or more of resistivity, neutron porosity, azimuthal gamma ray, density, elemental capture spectroscopy and sigma measurements. For example, consider features for one or more of 2 MHz and 400 kHz propagation resistivity, elemental capture spectroscopy, neutron-gamma density, capture cross section (sigma), azimuthal bulk density, azimuthal photoelectric factor, azimuthal natural gamma ray, density caliper, ultrasonic caliper, annular pressure and temperature while drilling, triaxial shocks and vibration, and near-bit borehole inclination. Such a tool may be operatively coupled to one or more telemetry systems that may provide for real-time acquisition and, for example, real-time decision making, rendering of graphics, etc. As an example, such a tool may be operatively coupled to one or more types of circuitries, which may, for example, perform computations downhole using measurements acquired downhole.

[0079] As an example, a tool such as the PERISCOPE tool (SLB, Houston, Texas) may be utilized to acquire measurements. For example, consider measurements such as resistivity, which may be acquired using one or more types of receivers. As an example, a receiver may be or include an antenna. For example, the PERISCOPE tool may include tilted, axial, and transverse antenna. As an example, data acquired from such a tool may provide for identification of layers, number of layers, position of a layer or layers, within a distance of 1 meter or more (e.g., up to or more than 8 meters).

[0080] As to sigma measurements (e.g., sigma data), sigma is the macroscopic cross section for the absorption of thermal neutrons, or capture cross section, of a volume of matter, measured in capture units (c.u.). A sigma log is the principal output of a pulsed neutron capture log, which may be used for one or more purposes.

[0081] As an example, one or more types of nuclear measurements may be acquired by one or more tools where such nuclear measurements may include one or more of electron density (ρe), hydrogen index (HI), and thermal neutron capture cross section (sigma or Σ).

[0082] As an example, geosteering may include intentional directional control of a wellbore based on results of downhole geological logging measurements in a manner that aims to keep a directional wellbore within a desired region, zone (e.g., a pay zone), etc. As an example, geosteering may include directing a wellbore to keep the wellbore in a particular section of a reservoir, for example, to minimize gas and / or water breakthrough and, for example, to maximize economic production from a well that includes the wellbore.

[0083] Referring again to FIG. 2, the wellsite system 200 may include one or more sensors 264 that are operatively coupled to the control and / or data acquisition system 262. As an example, a sensor or sensors may be at surface locations. As an example, a sensor or sensors may be at downhole locations. As an example, a sensor or sensors may be at one or more remote locations that are not within a distance of the order of about one hundred meters from the wellsite system 200. As an example, a sensor or sensor may be at an offset wellsite where the wellsite system 200 and the offset wellsite are in a common field (e.g., oil and / or gas field).

[0084] As an example, one or more of the sensors 264 may be provided for tracking pipe, tracking movement of at least a portion of a drillstring, etc.

[0085] As an example, the system 200 may include one or more sensors 266 that may sense and / or transmit signals to a fluid conduit such as a drilling fluid conduit (e.g., a drilling mud conduit). For example, in the system 200, the one or more sensors 266 may be operatively coupled to portions of the standpipe 208 through which mud flows. As an example, a downhole tool may generate pulses that may travel through the mud and be sensed by one or more of the one or more sensors 266 (e.g., consider mud-pulse telemetry). In such an example, the downhole tool may include associated circuitry such as, for example, encoding circuitry that may encode signals, for example, to reduce demands as to transmission. As an example, circuitry at the surface may include decoding circuitry to decode encoded information transmitted at least in part via mud-pulse telemetry. As an example, circuitry at the surface may include encoder circuitry and / or decoder circuitry and circuitry downhole may include encoder circuitry and / or decoder circuitry. As an example, the system 200 may include a transmitter that may generate signals that may be transmitted downhole via mud (e.g., drilling fluid) as a transmission medium.

[0086] Analysis of formation information acquired by one or more tools may reveal features such as, for example, vugs, dissolution planes (e.g., dissolution along bedding planes), stress-related features, dip events, etc. As an example, a tool may acquire information that may help to characterize a reservoir, optionally a fractured reservoir where fractures may be natural and / or artificial (e.g., hydraulic fractures). A reservoir may be a porous formation where fluid may be within various pores of the porous formation and amenable to movement (e.g., to produce fluid from the reservoir). As an example, information acquired by a tool or tools may be analyzed using a framework such as the TECHLOG framework (SLB, Houston, Texas). As an example, the TECHLOG framework may be interoperable with one or more other frameworks such as, for example, the PETREL framework (SLB, Houston, Texas). As an example, a computational environment such as, for example, the DELFI environment (SLB, Houston, Texas) may be utilized, which may provide for utilization of the PETREL framework and other frameworks, optionally in interrelated manners.

[0087] FIG. 3 shows an example of a drilling assembly 300 in a geologic environment 301 that includes a borehole 303 where the drilling assembly 300 (e.g., a drillstring) includes a bit 304 and a motor section 310 where the motor section 310 may drive the bit 304 (e.g., cause the bit 304 to rotate and deepen the borehole 303).

[0088] As shown, the motor section 310 may include a dump valve 312, a power section 314, a surface-adjustable bent housing 316, a transmission assembly 318, a bearing section 320 and a drive shaft 322, which may be operatively coupled to a bit such as the bit 304. The motor section 310 of FIG. 3 may be a POWERPAK family motor section (SLB, Houston, Texas) or another type of motor section.

[0089] A power section may convert hydraulic energy from drilling fluid into mechanical power to turn a bit. For example, consider the reverse application of the Moineau pump principle. During operation, drilling fluid may be pumped into a power section at a pressure that causes the rotor to rotate within the stator where the rotational force is transmitted through a transmission shaft and drive shaft to a bit.

[0090] FIG. 3 also shows examples of components 340 such as, for example, sensors 350, circuitry 360 and a geosteering actuator 370. As shown, the sensors 350 may include a conductivity and dielectric sensor 352, a gamma sensor 354 and one or more other sensors 356. As shown, the circuitry 360 may include a processor 362, memory 364 and one or more other types of circuitries 366. As shown, the geosteering actuator 370 may be operatively coupled to the circuitry 360 and the sensors 350. For example, the circuitry 360 may process signals (e.g., measurements or sensor data) of the sensors 350 to generate one or more commands for actuation of the geosteering actuator 370. In the example of FIG. 3, the geosteering actuator 370 may provide for one or more of PDM actuation and bent sub actuation, for example, to orient the drill bit 304.

[0091] FIG. 4 shows an example of a drilling assembly 400 (e.g., a portion of a drillstring) that includes a bit 404 and a rotary steerable system (RSS) 410. As mentioned, an RSS may be utilized for directional drilling, including geosteering. As an example, the RSS 410 may include one or more features of a POWERDRIVE ARCHER RSS (SLB, Houston, Texas).

[0092] FIG. 4 also shows examples of components 440 such as, for example, sensors 450, circuitry 460 and a geosteering actuator 470. As shown, the sensors 450 may include a conductivity and dielectric sensor 452, a gamma sensor 454 and one or more other sensors 456. As shown, the circuitry 460 may include a processor 462, memory 464 and one or more other types of circuitries 466. As shown, the geosteering actuator 470 may be operatively coupled to the circuitry 460 and the sensors 450. For example, the circuitry 460 may process signals (e.g., measurements or sensor data) of the sensors 450 to generate one or more commands for actuation of the geosteering actuator 470. In the example of FIG. 4, the geosteering actuator 470 may provide for RSS actuation, for example, to orient the drill bit 404.

[0093] As an example, the drilling assembly 400 may include one or more of a near-bit continuous inclination and azimuth measurement unit or sub, a near-bit azimuthal gamma ray measurement unit or sub, and one or more other types of measurement units or subs.

[0094] As an example, a drilling assembly may include one or more types of circuitries. For example, consider a processing unit with a processor and associated memory where one or more sensors may generate signals that may be received by the processing unit. In such an example, the processing unit may perform computations that may utilize information in the signals (e.g., measurements, etc.) to generate commands for geosteering. In such an example, a drilling assembly may be capable of performing, at least in part, downhole geosteering according to geosteering commands generated downhole without transmission of information uphole to a controller and subsequent transmission of information downhole to geosteering equipment. In such an example, at least some types of geosteering processes may be performed more rapidly in response to sensor signals. For example, consider sensor signals indicative of one or more of presence of clay, an amount of clay, a type of clay, and a boundary as an interface between layers, where downhole geosteering equipment may act to steer a drill bit based on one or more of such sensor signals.

[0095] As an example, an electromagnetic conductivity measurement tool (ECM tool) may be implemented as a wireline tool and / or implemented as a LWD tool to generate permittivity and conductivity measurements at each frequency for one or more frequencies, which may be interpreted using a petrophysical model. In such an example, output parameters of the model may include water-filled porosity (hence water saturation if the total porosity is known) and water salinity. As an example, parameters that may be output using ECM tool measurements (e.g., induction, propagation, etc.) may include one or more of bulk formation cation exchange capacity (CEC), water saturation (Sw), connate water salinity, Archie cementation exponent and Archie saturation exponent.

[0096] FIG. 5 shows example logs 500 that include various measurements acquired by one or more downhole tools. For example, the logs 500 include spontaneous potential (mV), gamma ray (gAPI), resistivity (ohm.m), neutron porosity (percent), and bulk density (g.cm−3). The gamma ray response (track 1) distinguishes the low gamma ray value of sand from the higher value of shale. The spontaneous potential curve generally follows a trend similar to that of the gamma ray. The next column, referred to as a depth track (track 2), indicates the depth at which measurements have been acquired. Across the sandstone formation, the resistivity measurements (track 3) are noticeably higher in the hydrocarbon zone than in the water-saturated zone in the lower part of the sand. Both neutron porosity and bulk density (track 4) provide measures of porosity. Within the hydrocarbon-bearing zone, the separation of the curves varies depending on the type of fluid encountered.

[0097] As an example, logs may be acquired as to formation parameters versus depth where, from such logs, lithologies may be identified that may differentiate various type of rock. For example, consider differentiating between porous and nonporous rock, which may provide for identification of one or more pay zones in subsurface formations. In a given field or local geological province, certain formations may have distinctive characteristics that appear similar from one well to the next, providing geologists with a basis for locating the depths of various strata in the subsurface. For example, consider identification of formation tops, which may be tracked from logs of one well to logs of another well. In the example of FIG. 5, the logs 500 include variations with respect to shale and sand where a first interface may be referred to as formation top X and a second interface may be referred to as formation top X+1. In such an example, an interface may be referred to as a boundary, which may also be identifiable in one or more other types of data such as, for example, seismic data. As an example, a workflow may include correlation of seismic picks to geologic picks, such as formation tops interpreted from well logs, to improve model building, etc.

[0098] As to resistivity of rock, it is a measure of the degree to which rock may impede the flow of an electric current. As shown, resistivity may be expressed in units of ohm.m, noting that it may be measured in ohm.m2 / m. The reciprocal of resistivity is conductivity, which is typically expressed in terms of millimhos or mmhos. The ability to conduct electrical current is a function of the conductivity of water contained in pore space of rock. Pure water does not conduct electricity; whereas, salt ions found in most formation waters do provide for conduction of electricity. Brine-saturated rocks tend to have high conductivity and low resistivity, which may be seen in the resistivity log data of FIG. 5 at depths about 7,200 feet. Hydrocarbons, which are nonconductive, cause resistivity values to increase as the pore spaces within a rock become more saturated with oil or gas.

[0099] As to spontaneous potential (SP), it is a measurement of voltage difference between a movable electrode in a wellbore and a fixed electrode at the surface. This electrical potential is primarily generated as a result of exchanges of fluids of different salinities (e.g., salinity of drilling fluid and salinity of formation fluid). During the course of drilling, permeable rock within a wellbore may become invaded by drilling mud filtrate where, if the filtrate is less saline than formation fluid, negatively charged chlorine ions from formation water may cause the SP curve to deflect to the left from an arbitrary baseline established across impermeable shale formations. The magnitude of the deflection is influenced by a number of factors, including permeability, porosity, formation water salinity and mud filtrate properties. Permeable formations filled with water that is fresher than the filtrate will cause the curve to deflect to the right. Hence, by the nature of deflections, an SP log may indicate which formations are permeable. A permeable formation with a high resistivity may be more likely to contain hydrocarbons.

[0100] As shown in the logs 500, a gamma ray (GR) log may be included, along with one or more of multiple resistivity logs and porosity readings obtained from density, neutron, and / or sonic logs. As to GR log acquisition, a downhole tool may measure naturally occurring radioactivity from a formation where a GR log may help differentiate non-reservoir rocks (e.g., shales and clays) from reservoir rocks (e.g., sandstone and carbonates). Shales and clays tend to be derived from rocks that tend to contain naturally occurring radioactive elements, primarily potassium, uranium and thorium. As a consequence, shales and clays are more radioactive than clean sandstones and carbonates. Quartz and calcium carbonate produce almost no radiation. A log analysis may look for formations with low background radiation because they may have potential to contain moveable hydrocarbons.

[0101] Various resistivity tools may measure a formation at different depths of investigation (e.g., shallow, medium and deep). A resulting log may present shallow, medium and deep tracks. A shallow curve, charting the smallest radius of investigation, may indicate resistivity of a flushed zone surrounding a borehole; a medium curve may indicate resistivity of an invaded zone; and a deepest curve may indicate resistivity of an uncontaminated zone, which may be presumed to be a true formation resistivity; noting that such a curve may still be affected by the presence of mud filtrate. By evaluating separations between curves at different depths of investigation, an analysis may provide an estimation of a diameter of invasion by mud filtrate and may be able to determine which zones are more permeable than others.

[0102] As to formation bulk density, it provides a measure of porosity. The bulk density of a formation is based on a ratio of a measured interval's mass to its volume. In general, rock porosity tends to be inversely related to rock density. Formation bulk density may be derived from electron density of a formation. Such a measurement may be obtained by a logging device that emits gamma rays into a formation. Gamma rays may collide with electrons in a formation, giving off energy and scattering in a process known as Compton scattering. The number of such collisions is directly related to the number of electrons in a formation. In low-density formations, more of these scattered gamma rays are able to reach a detector than in formations of higher density.

[0103] As hydrogen tends to be a major constituent of both water and hydrocarbons and because water and hydrocarbons concentrate in rock pores, the concentration of hydrogen atoms may be used to determine fluid-filled porosity of a formation. Hydrogen atoms have nearly the same mass as neutrons. Neutron logging tools emit neutrons using a chemical source or an electronic neutron generator. When these neutrons collide with hydrogen atoms in a formation, they lose the maximal energy, slow down and eventually reach a very-low-energy state (e.g., a thermal state). The rate at which neutrons reach the thermal state is proportional to the hydrogen concentration or index (HI). Various neutron porosity tools measure HI, which may be converted to neutron porosity.

[0104] As an example, a sonic log may be used to determine porosity by charting the speed of a compressional sound wave as it travels through a formation. Interval transit time (Δt), measured in microseconds per meter or foot and often referred to as slowness, is the reciprocal of velocity. Lithology and porosity affect Δt. Dense, consolidated formations characterized by compaction at depth generally result in a faster (shorter) Δt while fluid-filled porosity results in a slower (longer) Δt. Measurements may be affected by formation and borehole conditions. In various instances, quality control processes may be performed on data. As an example, gas, fractures and lack of compaction may demand adjustments to be applied to a sonic log. Lithologies affect the density, neutron and sonic logs. Invasion of mud filtrate into porous formations affects resistivity readings, and temperature affects the resistivity of both filtrate and saline formation water.

[0105] As an example, directional drilling may involve drilling a number of different sections such as, for example, a build section, a landing section and a lateral section. In such an example, a build section may be a portion of a directional wellbore curve that may extend from a kick-off point (KOP) to another point. As to a landing section, it may be a portion of a wellbore beyond a build section where steering may be controlled in an effort to hit a target. A landing section may be composed of segments such as, for example, an upper segment, which may be referred to as an approach section, and a lower segment, which may be referred to as a taper section. In the approach section, the magnitude of changes may tend to be greater than in the taper section as the taper section may aim to form a wellbore that smoothly transition at the end of the landing as the drillstring enters a target zone (e.g., a target formation). As to a lateral section, it may be a portion of a wellbore that extends substantially horizontally from an end of a landing taper, out to an end of the wellbore. A course change within a lateral section may affect a reservoir for better or for worse. As an example, a lateral section may be drilled using a BHA, which may include a mud motor, an RSS, etc. In various scenarios, inclination and / or azimuth of a lateral section may be maintained through a combination of sliding and rotating of a drillstring.

[0106] As an example, directional drilling may include geosteering as part of a landing job (e.g., drilling a landing section). In a landing job for a well, estimated well tops in the current well may lack accuracy. For example, estimated well tops may be rough estimates based on data from one or more offset wells as may be visually assessed by one or more individuals. As explained, a drillstring may include one or more logging tools to acquire measurements while drilling (e.g., MWD, LWD, etc.). Thus, when a current well is being drilled, real-time log measurements may be acquired. Where such measurements are available, an assessment may involve performing a comparison of a current well's log data and log data from one or more other wells (e.g., log data from one or more offset wells) to generate a more accurate estimate of one or more well tops. Such an assessment may be referred to as log correlation during geosteering. During directional drilling, accurate estimation of well tops may provide for decision making. For example, consider decision making as to whether drilling has arrived one or more points along a trajectory (e.g., planned trajectory points, safety points, etc.). In various instances, a point may be associated with an operation (e.g., a downhole operation, etc.) that is to be performed. During a landing job, a decision may relate to termination of a landing section or a transition from one landing segment to another.

[0107] As explained, directional drilling may involve performing log correlation visually, for example, using a number of logs rendered to a display. In such an example, one or more well placement engineers may interact with a graphical user interface that may provide for rendering logs to a display and manually adjusting positions of logs with respect to one another, picking well tops, etc.

[0108] As an example, a framework may include one or more components and / or operatively coupled to one or more components for implementing an integrated predictive geosteering workflow. In such an example, components may provide for executing a structural update, a resistivity forward prediction and an uncertainty prediction.

[0109] As an example, a framework may include one or more plug-in components. For example, consider one or more PETREL framework plug-in components. As to the PETREL framework, it may operate in conjunction with one or more plug-ins. For example, a plug-in may instruct an instance of PETREL as to performance of one or more of techniques (e.g., import, export, computation, etc.). As an example, a plug-in may provide for launching one or more components within a PETREL framework environment, for example, executing using local resources and / or executing using remote resources (e.g., consider one or more of a workstation, a networked HPC cluster, a cloud platform, etc.).

[0110] As an example, a workflow may be implemented for execution in real-time using at least in part field data. In such an example, components may be coordinated to expedite execution, for example, by reducing number of calls and responses, logistic waiting times, etc. For example, consider a plug-in that may be a unified plug-in for implementation of sub-workflows in an integrated predictive geosteering workflow (IPG workflow). As an example, a framework may include one or more visualization components. For example, consider a component that may provide for implementing a method that creates visualizations of results from a number of sub-workflows, which may provide for improved interpretations.

[0111] FIG. 6 shows an example of a drillstring 610 with various BHA features and an example of a drillstring 620 with various BHA features. As an example, the drillstrings 610 and 620 may include one or more of the features of the drillstring assembly 250 of FIG. 2. As shown in the examples of FIG. 6, the drillstring 610 includes a drill bit 612 and a group of direction and inclination (D&I) sensors 614 that are positioned relatively close to the drill bit 612 while the drillstring 620 includes a drill bit 622, a group of D&I sensors 624 that are positioned relatively close to the drill bit 622, one or more other D&I sensors 626, a D&I gyroscope sensor 627, and one or more D&I MWD sensors 628. In such examples, the closer a sensor is to a drill bit, in general, the more accurately the sensor may provide an indication of a downhole position of the drill bit, which, as explained, may provide for hole bottom estimation (HBE). As explained with respect to the system 400, the data service 412 may acquire data for one or more purposes, which may include data for utilization by the state estimation component 414, which may provide for HBE.

[0112] As to a gyroscope sensor, consider, as an example, a gyroscope sensor that includes one or more features of the GYROSPHERE tool (SLB, Houston, Texas). As an example, a gyroscope sensor may provide for acquisition of gyro-surveying data in a manner that may help to an ellipse of uncertainty. As an example, a gyroscope sensor may include microelectromechanical systems (MEMS) technology that may utilize the Coriolis effect, for example, consider use of a vibrating structure that may provide for determination of a rate of planetary rotation. As an example, such a rate may be sensor data that may be utilized to determine one or more of inclination, azimuth, and toolface orientation. As an example, a gyroscope sensor may provide for survey data during a connection of drillpipe. For example, a measurement may be taken during a connection where the measurement may be available immediately after mud pumps are on (e.g., making data available more rapidly) due to MEMS technology not having to spin up and stabilize. As an example, two surveys may be performed in the time a non-MEMS gyroscope takes to start up for just one survey. As an example, a gyroscope sensor may be a MEMS technology-based sensor that may handle relatively severe shock and vibration. As an example, a single sensor may be utilized to survey at an inclination, at a depth, and at higher latitudes, without a demand for changing batteries or recalibrating between runs, which may make batch-drilling operations more efficient. As an example, one or more gyroscope sensors may be included on a drillstring. As an example, an RSS tool may include a gyroscope sensor. As an example, a drilling may include a gyroscope sensor in a module or unit that may be assembled on a drillstring (e.g., a tool with a length that makes up part of a length of a drillstring). As an example, an MWD tool may include a gyroscope sensor.

[0113] As an example, an MWD tool may include various sensors for acquiring data, which may include survey data such as, for example, direction and inclination (D&I) data. An MWD tool may be powered electrically using one or more mechanisms. For example, consider a battery, a fluid turbine generator, etc. Where multiple mechanisms are included, they may provide for redundancy and increased up-time. For example, a battery may provide for operation during intermittent drilling-fluid flow conditions. Battery power may also provide for logging during tripping in (running in hole (RIH)) or out of the hole (pulling out of hole (POOH)). As such, an MWD tool on a drillstring may acquire data for the same location multiple times as it passes the location during drilling, RIH, POOH, etc.

[0114] As to sensors, an MWD tool may include directional-sensor technology that may, for example, utilize an array of three orthogonal fluxgate magnetometers and three accelerometers. While standard directional sensors may provide acceptable surveys, in scenarios where uncertainty exists in a bottomhole location, more sophisticated sensor technology may help to reduce such uncertainty. Yet, as explained, even with more sophisticated sensor technology, uncertainty may still exist, which may be exacerbated by recent trends to drill longer and more complex wells. Various types of errors may also exist for MWD measurements, which may include, for example, one or more of sensor error, magnetic interference from the BHA, tool misalignment, and magnetic-field uncertainty.

[0115] As to MWD telemetry, mud-pulse telemetry is a standard method in various commercial MWD and LWD systems, noting that one or more other types of telemetry may be utilized, additionally or alternatively. Demands on telemetry may be imposed by real-time azimuth correction, which involve transmission of raw data to surface. Further, telemetry may introduce uncertainties when compression / decompression are utilized (e.g., with loss or lossless) and general types of transmission errors (e.g., noise, physical events, etc.).

[0116] As to an MWD survey, recordings of MD, inclination, and hole direction may be taken at a survey station where a number of survey stations may be obtained along a path. Such measurements may be used together to calculate 3D coordinates, which may then be presented as a table of numbers called a survey report. Surveying may be performed during a drilling run, while RIH, POOH, after drilling has been completed, etc. An MWD survey of an MWD tool of a drillstring demands that breaking rock with a drill bit of the drillstring is halted (e.g., drilling suspended) such that the MWD tool may remain stationary in an environment with diminished noise to acquire sensor data for the MWD survey. An MWD survey may be utilized for one or more purposes such as, for example, one or more of determining a bottomhole location to monitor reservoir performance, monitoring an actual path to help ensure a target will be reached, orienting deflection tools for navigating paths, reducing risks of intersecting a nearby well, computing the TVD of various formations to allow for geological mapping, evaluation DLS, and fulfilling requirements of regulatory agencies, such as the Minerals Management Service (MMS) in the US. As to the latter, if an ability to survey using an MWD tool on a drillstring becomes impractical or impossible, drilling may be terminated until the issue is resolved, for example, to assure compliance with regulatory requirements, to reduce risk of colliding with another borehole, wellbore, etc.

[0117] Where an RSS tool is utilized, one or more of downlinks and uplinks may be employed. Downlinks may be commands transmitted for receipt by an RSS tool. Such downlinks may employ rotational techniques such as adjusting drillstring RPM as a signal (e.g., via a top drive) that encodes a command and / or flow techniques such as adjusting flow of drilling fluid (e.g., mud) as a signal (e.g., via one or more mud pumps) that encodes a command. As an example, one or more techniques may involve use of a surface listener as a type of equipment that may sense the RPM and / or flow adjustments. For example, a surface listener may sense pressure and then associate sensed pressure data with downlink codes. In such an example, the surface listener may understand and confirm downlinks to an RSS tool (e.g., knowing what commands may have been sent). A surface listener may be helpful in the instance where, for one or more reasons, uplinks are not possible or otherwise unreliable. For example, an uplink may be a signal generated by an RSS tool that is destined for receipt by an MWD tool where the MWD tool may employ mud-pulse telemetry to convey the signal (e.g., or content thereof) to surface.

[0118] As an example, an RSS tool may include sensors that may provide for measurements of one or more of inclination offset to tool bottom, azimuth offset to tool bottom, average gamma ray, gamma ray offset to tool bottom, vibration axial, vibration radial, shock, triaxial shock and vibration axis, magnetic field cone of exclusion, etc. As an example, sensors may include one or more of gyroscopic sensors, accelerometers, magnetometers, gamma ray sensors, shock and vibration sensors, pressure sensors, temperature sensors, etc. As an example, sensors may be arranged as a group or a package. As explained, a sensor or sensors may be positioned along a drillstring, which may be at one or more distances from a drill bit of the drillstring.

[0119] As explained, an RSS tool may include D&I sensors and / or one or more other sensors that acquire data where the data may be stored locally and / or transmitted. As explained, an RSS tool may utilize uplink technology to transmit data from the RSS tool to an uphole MWD tool, as may be located a distance from the RSS tool on a common drillstring.

[0120] As an example, where a mud motor is utilized on a drillstring with an MWD tool and without an RSS tool, data from the MWD tool may be utilized in a mud motor mode. In various instances, a drillstring may include an MWD tool and may include a mud motor and an RSS tool; whereas, in general, a mud motor or an RSS tool will be present for directional drilling.

[0121] As explained, a borehole may have a direction and a borehole bottom (e.g., hole bottom (HB) or bottom of hole (BH)) may have an orientation. For example, consider a borehole orientation that may be described in terms of inclination and azimuth. Inclination generally refers to the vertical angle measured from the down direction where down, horizontal, and up directions have inclinations of 0 degrees, 90 degrees and 180 degrees, respectively. Azimuth generally refers to the horizontal angle measured clockwise from north, which may be a type of “north” or defined “north”. In general, north, east, south and west directions have azimuths of 0 degrees, 90 degrees, 180 degrees and 270 degrees, respectively. In drilling, azimuth may be defined as a compass direction of a directional survey or of a wellbore as planned or measured by a directional survey where, for example, the azimuth may be specified in degrees with respect to a geographic north, a magnetic north pole, or another defined “north”. As an example, an HB may be defined as a flat surface (e.g., a planar surface) with an orientation that may be defined by a vector that points in a direction normal to the flat surface. In such an example, an HB may be defined by a position (e.g., a measured depth) and an orientation (e.g., a direction). As an example, a system may provide for maintaining proper reference to one or more directions (e.g., north, south, east, west, etc.). Maintaining proper reference may facilitate directional drilling in relatively thin layer reservoirs that may have an upper true vertical depth (TVD) limit and a lower TVD limit. Geosteering in such reservoirs may be challenging though improved when a proper reference is maintained (e.g., to assure proper reservoir contact between a borehole and a reservoir). As explained, a system may help to maintain a proper reference through developing a series of estimated HBs (e.g., position and orientation) along a borehole.

[0122] As an example, one or more types of measurements may provide for assessing uncertainty of one or more other types of measurements. For example, temperature may be utilized to assess uncertainty of a sensor with respect to its operational temperature range. In such an example, if a temperature is measured that is outside of an operational temperature range for a sensor, measurements from that sensor may have greater uncertainty.

[0123] As an example, an earth model may provide for pressure and temperature modeling with respect to depth (e.g., true vertical depth (TVD)). In such an example, measured pressure and / or measured temperature may be compared to values, gradients, etc., of an earth model, which may help to increase accuracy of and / or otherwise check a HB position (e.g., an HBE).

[0124] As mentioned, a working plan may be or include a trajectory to construct a path from a current bit location (e.g., a HB position) to a next target location (e.g., a desired HB position). As an example, a framework may include features that may implement an automatic method to estimate the position of a bottom of a hole (BH or HB) during well construction execution. For example, along a BHA, the position of one or more sensors that may be used to estimate a location of a borehole may be within three meters of a drill bit (e.g., less than approximately three meters but greater than approximately 20 cm) or they may be a considerable distance from a drill bit (e.g., more than 3 m, 5 m, 10 m, 30 m, etc.). In such an example, where measurements of sensors are used, some type of predictive model is generally required to estimate the exact, actual location of a bottom of a hole (HB). For example, even when a group of sensors is located within one meter of a drill bit, an estimation or prediction may be required for an HBE. As an example, a framework may include one or more features that may improve HBE where such one or more features may provide for more accurate and automated estimation of the exact, actual location of a bottom of a hole (BH or HB).

[0125] As an example, a framework may include one or more features for optimal filtering that consumes, in real-time (RT), one or more types of downhole information (e.g., D&I, etc.) for providing an estimation of one or more HB parameters, for example, with uncertainties and continuous trajectory interpolation along with extrapolation outputs. In such an example, the framework may provide for estimation of HB position and / or drill bit position during directional drilling activities.

[0126] As mentioned, modern wells may be relatively complex and thereby pose an increased number of risk and reward scenarios for proper planning and execution. As to automation, whether in planning and / or execution, automation may aim to de-skill and de-man a directional drilling process while ensuring efficiency and consistency. For example, with automation, demand for on-site personnel may be lessened (e.g., fewer people) and / or skill level(s) of on-site personnel may be lessened and / or shifted (e.g., shifted to automation oversight versus directional drilling decision making).

[0127] As explained, an autonomous directional drilling (DD) system may aim to achieve one or more goals, for example, through use of an automated directional drilling advisor framework that provides real-time optimal decision-making. As an example, an autonomous DD system may provide for automation levels of various workflows. For example, consider one or more workflows motor control, trajectories, commands and / or downlink recommendations for one or more RSSs. Such an autonomous DD system may be suitable for one or more of multiple types of wells where it may automatically provide, from start to end of a section, at each survey point, an appropriate next sequence of actions.

[0128] FIG. 7 shows an example of a portion of a wellbore 702 (e.g., a borehole) with respect to an r, z coordinate system (e.g., a cylindrical coordinate system) as penetrating a portion of a subterranean formation 710 (e.g., a sedimentary basin, etc.). As shown in the example of FIG. 7, a drillstring 712 may be positioned at least in part in the wellbore 702 where the drillstring 712 may include a tool (or module) 720 (e.g., a measurement tool, a logging tool, etc.) and telemetry equipment 740 (e.g., which may be part of the tool 720 or another tool).

[0129] As shown in the example of FIG. 7, the wellbore 702 includes casings 704-1 and 704-2 having casing shoes 706-1 and 706-2. As shown, cement annuli 703-1 and 703-2 are disposed between the wellbore 702 and the casings 704-1 and 704-2. Cement such as the cement annuli 703-1 and 703-2 can support and protect casings such as the casings 704-1 and 704-2 and when cement is disposed throughout various portions of a wellbore such as the wellbore 702, cement can help achieve zonal isolation.

[0130] In the example of FIG. 7, the wellbore 702 has been drilled in sections or segments beginning with a large diameter section (see, e.g., r1) followed by an intermediate diameter section (see, e.g., r2) and a smaller diameter section (see, e.g., r3). As an example, a large diameter section may be a surface casing section, which may be three or more feet in diameter and extend down several hundred feet to several thousand feet. A surface casing section may aim to prevent washout of loose unconsolidated formations. As to an intermediate casing section, it may aim to isolate and protect high pressure zones, guard against lost circulation zones, etc. As an example, intermediate casing may be set at about 6000 feet and extend lower with one or more intermediate casing portions of decreasing diameter (e.g., in a range from about thirteen to about five inches in diameter). A so-called production casing section may extend below an intermediate casing section and, upon completion, be the longest running section within a wellbore (e.g., a production casing section may be thousands of feet in length). As an example, production casing may be located in a target zone where the casing is perforated for flow of fluid into a lumen of the casing.

[0131] Prior to introducing cement into an annulus between a bore and a casing, calculations may be performed to estimate an amount of cement sufficient to fill the annulus, for example, for purposes of sealing off a casing segment. Accuracy of an estimate as to the amount of cement as well as issues in a process of introducing cement may, for example, result in occasional voids or gaps (e.g., regions where cement is lacking). Depending on the nature of such voids or gaps, casing or borehole integrity may be at risk or compromised. However, where one or more integrity detection techniques can be implemented, it may be possible to detect voids or gaps and call for remedial action, alteration of a plan, etc.

[0132] As an example, equipment may provide for detecting casing magnetic interference in real-time. In such an example, the equipment may include circuitry where such circuitry may provide for generation of data that may be consumed by a computational framework. In such an example, the computational framework may provide for improved control of one or more drilling operations, which may include, for example, one or more of planning, re-planning, hydraulics control, drawworks control, top drive control, steering control, etc.

[0133] As explained, a drillstring may include an MWD tool that may utilize a combination of three orthogonal magnetometers and accelerometers to determine azimuth and inclination of a tool-face (e.g., drill bit tool-face (TF)). As explained, knowledge of azimuth and inclination (AZ and INCL) may provide for proper directional drilling, which may include geosteering. However, as explained, a wellbore may include one or more cased portions where such casing may be metallic. Being metallic, casing may serve as a source of intense magnetic interference to a magnetometer, thus compromising magnetometer performance, readings, etc. For example, magnetic interference from metallic casing may impede a tool's ability to adhere to a planned trajectory of a well. As an example, equipment may be configured to provide for detecting and indicating the presence of metallic casing in real-time. For example, consider a method that may provide for detecting and flagging the presence of metallic casing in real-time by analyzing patterns in tool sensor data as may be acquired and streamed in real-time. In such an example, a framework may provide for issuance of one or more casing-related signals responsive to receipt of tool sensor data as may be acquired and streamed in real-time.

[0134] As to interference, consider how a magnetometer may exhibit relatively erratic behavior when it is within a cased section of a well, surrounded peripherally by metallic casing. In such a scenario, a magnetometer response may be assessed in multiple dimensions, which may include a temporal dimension. For example, consider multiple spatial dimensions and a temporal dimension. As an example, for a given set of magnetometer data, a 3D spatial approach may be taken for a window in time. As an example, a framework may provide for an assessment of erratic behavior in three spatial dimensions of a magnetometer response in one or more cased regions of a wellbore.

[0135] As an example, a framework may provide for assessing a vector sum of radial channels that may show substantially noisy and unreliable readings for a cased region while registering relatively clean, sensible data soon after descending past a cased region into an uncased region. As an example, a framework may provide for acquiring measurements (e.g., observations) from one or more downhole runs and performing one or more analyses as to statistical properties. In such an example, based on such initial observations, analyses on statistical properties may be developed where, for example, one may involve tracking the rate at which values progress, and where, for example, one or more others may be based on circularity of a plot of one or more radial channels.

[0136] As an example, a framework may provide for unsupervised learning. For example, consider an approach whereby data are acquired and processed in an unsupervised manner to generate one or more trained and / or selected models, techniques, etc. As an example, consider a framework that may utilize unsupervised algorithms, and an optimal combination of explored methodologies to enable generation of a reliable prediction. In various example trials, as explained herein, a combined solution approach may provide for quantifying uncertainty of predictions as well as investigation of one or more reasons for one or more underperforming runs.

[0137] In a particular example trial, a test dataset, composed of historical field data, covered a comprehensive expanse of well-trajectory and rig types, from different locations. The performance of various approaches was scored against a label defined by domain knowledge. Each of the various approaches was compared and ranked on the basis of accuracy in predicting the correct label. As explained, as an approach may be for real-time utilization, for example, using circuitry embedded in a drillstring (e.g., a downhole tool or tools), a model-based approach may be tailored to a relatively low-RAM capacity and, for example, adapted on prediction delay.

[0138] As explained herein, a framework may be implemented using downhole circuitry or, for example, downhole and surface circuitry, that can leverage various unique properties of downhole tool data to inform a tool as to when it has left a cased region. In such an example, a tool may provide for conserving various processing functions, energy, data transmissions, etc., for sensor data that have assurances that risk of interference from metallic casing (e.g., noise, erratic data, etc.) is reduced. For example, circuitry of a tool may provide for triggering one or more functions of the circuitry upon an indication that acquired sensor data are relatively clean and free from interference. As an example, a framework may provide for improving one or more ranging systems, imaging processes, etc., that utilize magnetometer data. As an example, a framework may provide for detecting and / or validating a recorded casing shoe-depth. As an example, a framework may provide for improved automation. For example, consider a framework that may provide for improved sensor data that may be more reliable for an automated controller, which may provide for control of one or more types of equipment involved in one or more drilling operations, which may include, for example, one or more of tripping (e.g., in or out), drilling using one or more modes, geosteering, etc. As explained, a framework may provide for improved planning, re-planning, control, etc. As an example, rig automation may be improved via a technique that provides for detection of metallic casing and one or more ends of casing. As explained, various techniques may provide for improved efficiency of one or more directional drilling processes.

[0139] As an example, a system can include circuitry for detecting casing magnetic interference in real-time. As an example, such circuitry may be disposed in a drillstring or, for example, in a drillstring and surface equipment where telemetry is utilized to transmit data from the drillstring to one or more pieces of surface equipment. As explained, telemetry may be utilized to transmit data between downhole tools, from a downhole tool to another downhole tool, and / or from a downhole tool to surface equipment.

[0140] As explained, MWD tools may use a combination of three orthogonal magnetometers and accelerometers to determine azimuth and inclination of a tool-face (TF). As explained, TF may be an angle measured in a plane perpendicular to a drillstring axis that is between a reference direction on the drillstring and a fixed reference. For example, for near-vertical wells, north may be a fixed reference and an angle may be a magnetic toolface. As an example, for more-deviated wells, the top of a borehole may be a fixed reference and an angle may be a gravity toolface, or high side toolface.

[0141] As explained, casing may be metallic and a source of relatively intense magnetic interference to a magnetometer. As explained, a magnetometer is an instrument that includes components and circuitry for measuring strength or direction of the Earth's magnetic field. As an example, a magnetic field may be represented using a vector notation and a coordinate system. For example, consider a Cartesian coordinate system, a cylindrical coordinate system, a spherical coordinate system, etc. As an example, for a Cartesian coordinate system with orthogonal axes, consider x-axis, y-axis, and z-axis, three-axis readings may be defined as Bx, By and Bz. In a cased portion or portions of a borehole, one or more of these readings may be compromised. Where such interference occurs, an MWD tool may be challenged in computing an accurate azimuth value, which, in turn, may impede an ability to adhere to a planned or otherwise desirable trajectory of a borehole.

[0142] As explained, an MWD tool may also include an accelerometer (or accelerometers). As an example, an MWD tool may generate data that includes accelerometer data (e.g., Gx, Gy and Gz) and magnetometer data (Bx, By and Bz). As an example, an MWD tool may also generate temperature data and / or one or more other types of data. As explained, surface equipment may receive and processes MWD data to generate values for one or more of azimuth, inclination, total gravity field, gravity tool face, magnetic tool face, total magnetic tool face, and dip angle. As an example, a framework may provide for generate an indicator, a value, etc., as to a cased portion or cased portions of a borehole, which may include a transition point as to a transition between a cased portion and an uncased portion of a borehole. For example, consider generation of an indicator, a value, etc., as to a casing shoe position (e.g., a casing shoe measured depth, etc.).

[0143] As an example, a framework may provide for utilization of one or more of a number of techniques. For example, consider an approach that implements four different techniques that utilize raw data from a magnetometer (or magnetometers) and analyze patterns that may point to presence of casing. As an example, such a framework may operate by comparing acquired data to what may be expected for ideal conditions. For example, consider an approach that involves analyzing rate-of-change of readings, which may utilize one or more properties of a circle resulting from a plot of Bx versus By (e.g., or other appropriate geometric construct). For example, where a circle is utilized, eccentricity and spread of datapoints may be fit to an equation for an ellipse and, for example, a comparison performed as to a recorded BT value (e.g., a sum of Bx and By) to an ideal, predicted BT value (e.g., a sum of predicted Bx and By or merely a predicted BT).

[0144] As an example, a framework may provide for generating an indicator (e.g., a flag, a trigger, etc.) responsive to the presence of casing in real-time by analyzing three-axis input readings from a magnetometer in an MWD tool. In such an example, a result may be a combination of predictions from four or more separate techniques, as may be developed based on unique properties of input data during cased periods and uncased periods, for example, as a drillstring with an MWD tool is being moved within a borehole.

[0145] As explained, a framework may operate in real-time. To achieve real-time performance, latencies or other types of delays may be minimized, particularly as to circuitry to generate predictions in real-time. As explained, circuitry may be embedded in a drillstring such as within an MWD tool. In various instances, an MWD tool or other tool that includes one or more magnetometers may possess a limited amount of memory (e.g., hardware for storing data, commands, etc.). As an example, a framework may be a computational framework that may be relatively lightweight. As an example, such a framework may provide for generating predictions using a limited amount of information (e.g., data, etc.). As an example, a framework may operate in a manner that is restricted to tool dump data without use of one or more surface channels. As an example, such tool dump data may be data that is amenable to reading at surface upon pulling a drillstring out of a borehole and / or data that may be amenable to transmission via telemetry (e.g., mud-pulse telemetry, etc.).

[0146] As an example, a method may involve a magnetometer acquiring readings determining orientation of a tool-face (or toolface or TF) with respect to the Earth's magnetic field in three dimensions, Bx, By and Bz. These readings may be quite susceptible to magnetic interference and give noisy outputs when in close proximity to casing. As an example, noise may be characterized together with signal (e.g., signal-to-noise ratio (SNR), etc.) and / or via one or more other techniques, metrics, etc.

[0147] As explained, a borehole may be considered to be, on an incremental basis, cylindrical. As explained, for deviated boreholes, direction, orientation, etc., of the cylinder changes with respect to depth for at least a portion over a total measured depth. For example, for a vertical portion of a borehole hole, a cylinder may be representative of that vertical portion; whereas, for a dog-leg, multiple cylindrical intervals may be utilized. And, for a horizontal portion, one or more cylindrical intervales may be utilized, the number of which may depend on how a reservoir region varies with spatially in a subsurface environment.

[0148] Given a cylindrical representation of a portion of a borehole and a Cartesian coordinate system representation of a magnetometer vector, a z-axis may be considered aligned with a longitudinal axis of the borehole; whereas, an x-axis and a y-axis may be considered to be planar where the z-axis is normal to a plane defined by the x-axis and y-axis. With respect to a cylindrical borehole, the plane defined by the x-axis and y-axis may be considered to be a radial plane where, for example, Bx and By represent radial components of the magnetometer vector.

[0149] As an example, a framework may consider that the radial axes (Bx and By) suffer effects of interference from casing to a greater extent that the longitudinal axis (Bz), where the radial axes values may exhibit relatively erratic jumps in readings in the presence of casing. As a magnetometer exits a cased portion of a borehole, such behavior may cease. For example, consider an MWD tool descending in a borehole where once the MWD tool descends out of a cased region of the borehole, erratic nature of radial axes readings dissipates. As an example, a technique may involve utilization of a vector sum. For example, a vector sum of Bx and By, denoted BT, may give a thorough outlook of this effect on these axes through use of BT as a single value (e.g., a single metric to indicate a transition from a cased region to an uncased region or vice versa).

[0150] As explained, during drilling a drillstring or at least a portion thereof rotates. For example, during a sliding mode using a mud motor to rotate a drill bit, a drillstring may be oscillated at surface and / or remain stationary at surface; whereas, in a rotary mode, a drillstring is rotated using surface equipment (e.g., a top drive, a rotary table, etc.). As an example, an MWD tool may be located on a portion of a drillstring such as on a BHA, which may include a mud motor. Depending on location of the MWD tool, it may or may not rotate responsive to rotation of a mud motor. For example, if the MWD tool is uphole from a mud motor, it may rotate responsive to surface driven rotation of a drillstring but not responsive to mud motor rotation of a drill bit of the drillstring.

[0151] As an example, where a tool that includes one or more magnetometers rotates, a circular pattern may be formed by values of Bx and By when plotted against each other. In such an example, in the absence of casing, the resulting plot may be close to a perfect circle. However, in the presence of casing, the resulting plot may form relatively random, incoherent patterns. As an example, a framework may provide for comparing an ideal circle (e.g., as a magnetometer performance feature) to input data (e.g., radial plane data) to thereby make a prediction as to casing status. For example, consider an approach that assesses how close plotted data are to an ideal case. In such an example, the closer the input data are to forming a perfect circle, the more likely it is that the tool is not within a cased portion of a borehole (e.g., past casing and into an open hole portion of a borehole). As an example, such a comparison may be performed by finding an ellipse-of-best-fit over a set of data and analyzing fit parameters.

[0152] FIG. 8 shows an example plot 800 of BT versus time during movement of a drillstring in a borehole with a cased portion and an uncased portion. As indicated, these data stabilize in a manner that corresponds to movement from the cased portion to the uncased portion (e.g., open hole portion) of the borehole. As an example, such data may be assessed as to a particular time, which may be associated with a particular distance (e.g., a measured depth, etc.), for example, to indicate an end of casing, which may be a casing shoe-end.

[0153] FIG. 9 shows example plots 910 and 920 of radial axes data, particularly Bx versus By, for a magnetometer where the plot 910 corresponds to a cased portion of a borehole and where the plot 920 corresponds to an uncased portion of a borehole. In the examples of FIG. 9, the data of each of the plots 910 and 920 may be data acquired with respect to a period of time, which may be a time window. As explained, data may be acquired while a tool that includes a magnetometer is rotating. Given such rotation, a plot of data of the individual axes (e.g., Bx and By) may be expected to form a circle, as shown in the plot 920; whereas, where interference exists due to metallic casing, these data may not form a circle, but rather, a distorted pattern that is not substantially circular as may be determined using equations for an ellipse and / or one or more other geometric constructs.

[0154] As an example, a framework may assess data with respect to one or more clusters. For example, consider an approach that may consider one or more dense clusters or density of a cluster or clusters. As an example, while steering a drillstring, sensors of a magnetometer may be temporarily concentrated in one direction, resulting in a Bx versus By plot looking like a cluster of points in one corner, which may affect performance of technique as these data may not form a complete circle (e.g., consider how rotation may provide for formation of a circle, etc.). As an example, a framework may discern one or more of such periods in time by assessing an Rx value. For example, one or more metrics, thresholds, etc., may be utilized to determine if a tool may be steering or not. For example, consider utilization of an equation such as LV<Rx<HV, where LV may be a low value and where HV may be a high value. In such an example, consider LV being approximately −1.5 and HV being approximately 1.5 where an Rx value within this range may indicate steering; whereas, if an Rx value is outside of this range, then that may indicate not steering. As an example, a framework may automatically indicate that these values correspond to an uncased portion of a borehole (e.g., an open hole portion). As an example, a framework may automatically set such values to a status as “uncased”.

[0155] As to the aforementioned Rx value, it may be determined using a particular gyroscope, which may be referred to as a “roll gyro”. Such a gyroscope may be an independent gyroscope that is included as a downhole instrument (e.g., as part of an MWD tool, etc.) to measure rotation speed of a drillstring and / or one or more components thereof. As an example, an Rx value may be a roll gyro measurement that may provide information as to whether a tool is trying to steer or is in a neutral position. As an example, an Rx value may be close to 0 when trying to steer and, for example, between approximately −2 and approximately −4 when neutral; noting that one or more types of references, scalings, transforms, etc., may be applied to a roll gyro measurement (e.g., Rx) to provide for suitable values that may be assessed using one or more techniques (e.g., thresholds, etc.).

[0156] FIG. 10 shows example plots 1010 and 1020 for data points that tend to be concentrated in a cluster when a drillstring is involved in steering. As shown in the plots 1010 and 1020, index numbers for Bx versus By are plotted where Rx may be assessed.

[0157] As an example, for data of frequency 5 Hz, a tool may receive 300 datapoints per minute. As an example, a framework may provide for setting a time period, a time interval, a time window, etc., based at least in part on an acquisition frequency. For example, consider an approach where a criterion may be given as a number of datapoints. In such an example, consider a criterion that calls for at least 100 datapoints, at least 200 datapoints, at least 300 datapoints, etc. In various example, trials, approximately 300 datapoints (e.g., plus or minus 15 percent) was deemed sufficient for robust and reliable performance. Where a frequency for data acquisition is 5 Hz, in a period of one minute, 300 datapoints may be acquired, which may be processed to make a real-time prediction (e.g., a prediction as to cased or uncased at an interval of approximately one minute). As an example, a framework may provide for implementing a technique where sensor readings values are forward-filled to take care of missing values.

[0158] As explained, a framework may utilize a number of techniques, which may include a rate-of-change (ROC) of BT value technique, an eccentricity of ellipse-of-best-fit (EBF) technique, a degree of spread of raw data from a fitted ellipse (SFE) technique, an ideal BT and diameter of an ellipse (IBT) technique, etc.

[0159] As to the ROC technique, as observed in FIG. 8, values during cased regions jump around erratically but seem sensible for the remainder of a downhole run. In such an example, a framework may infer that the rate-of-change (ROC) of the BT value will be extremely steep when compared to the general trajectory of the uncased region. As an example, an average value of a 300-datapoint window may be computed. Next, the ROC between this average and the average of the next 300 datapoints (e.g., with no step value in between) may be computed. In such an example, if the mode of the percent change of the ROC is above a threshold of 0.0003, the datapoints in that window may be classified as “cased”.

[0160] As to an EBF technique, as explained, eccentricity of an ellipse may be a suitable measure of how circular data are when plotted. For example, a perfect circle has eccentricity of 0. In such an approach, if an ellipse-of-best-fit computed on a 300-datapoint window is close to 0 (e.g., within some tolerance threshold), the data points in that window may be classified as “uncased”.

[0161] As to a SFE technique, which may consider degree of spread of raw data from a fitted ellipse, consider an altered version of an equation of an ellipse, where the equation is given below followed by the altered version:x2a2+y2b2=1B⁢x2b2+B⁢y2a2=1where a and b represent the semi-minor and semi-major axes respectively.In this example SFE technique, when substituting the values of Bx and By with the sensor readings, if the result is equal to 1, it insinuates that the raw data are more or less on the fitted ellipse. If the equation result is approximately equal to 1 for a 300-datapoint window, all datapoints in that window may be classified as “uncased”.

[0163] As to an IBT technique, which may consider an ideal BT and diameter of an ellipse, as an example, a theoretical ideal BT value may be computed for a certain point in a run, for example, using the following formula:BT=B⁢(1-(cos⁢ I)⁢(sin⁢ D)+(cos⁢ A)⁢(cos⁢ D)⁢(sin⁢ I)2where B=predicted value of Earth's magnetic field in that region, I=inclination, D=magnetic dip angle, and A=azimuth.In the foregoing equation, as azimuth values tend to be contaminated from faulty magnetometer readings, such an equation may be adapted to a lower and upper bound, for example, by assuming the values of cosA to be at least −1 and at most 1:BT=B⁢(1-(cos⁢ I)⁢(sin⁢ D)+(cos⁢ D)⁢(sin⁢ I)2BT=B⁢(1-(cos⁢ I)⁢(sin⁢ D)-(cos⁢ D)⁢(sin⁢ I)2As an example, a framework may provide for computed a BT value as BT=√{square root over (Bx2+By2)}. In such an example, if the average of the recorded BT values of a 300-datapoint window is either within the range of the two predicted BT values or approximately equal to either one of them, datapoints in that window are classified as “uncased”.

[0166] As an example, a framework may provide for making a final prediction that may rely on a number of predictions. For example, a final prediction may be based on a combination of results of two or more of the aforementioned techniques. As an example, a datapoint or datapoints may be classified as “cased” if a majority vote is determined from a number of individual techniques. As an example, if there is a tie, a framework may automatically classify as an “uncased” scenario. As an example, a framework may provide for quantifying uncertainty of one or more predictions, for example, by counting the number of techniques that voted “cased”.

[0167] As an example, a framework may provide for making rapid determinations using a number of different techniques where the framework may provide for generating a number of classifications using two or more combinations of different techniques. For example, consider an approach where four techniques are applicable for a framework where combinations can include two techniques, three techniques, and four techniques. In such an approach, ten different combinations may be possible where uncertainties may be generated for each of the different combinations. As to two techniques, 50 percent or 100 percent may result; as to three techniques, 33 percent, 66 percent, or 100 percent may result; as to four techniques, 25 percent, 50 percent, 75 percent, or 100 percent may result. As an example, upon acquisition of sufficient data, a framework may resort to weighting outcomes from individual techniques. As an example, a framework may provide for selecting a particular combination of techniques based on performance.

[0168] As an example, a method may include determining whether a magnetometer is in proximity of magnetic interference in a borehole. In such an example, the method may employ a number of techniques, which may be selected from a group of techniques. As an example, a method may involve tracking the rate-of-change of BT over a short window of time; and comparing a plot of Bx versus By to ideal conditions of one or more of (i) eccentricity, (ii) semi-major and semi-minor axes, (iii) diameter, and (iv) degree of spread of datapoints from a fitted ellipse.

[0169] As an example, a method may provide for using one or more techniques independently and / or within one or more permutations of a group of such techniques.

[0170] As an example, a method may include implementing a criterion as to number of datapoints to be considered to form a dataset, which may be within a time window. For example, consider a 300 datapoint long window. As an example, a method may include adjusting a criterion, which may be adjusted based on one or more conditions, which may depend on certainty, uncertainty, speed of a tool being moved in a borehole, rotation rate of a drillstring, etc. As an example, a 300-datapoints long window may be increased and / or decreased to a desired length as per one or more domain requirements and / or tool configuration.

[0171] As an example, a framework may provide for implementing one or more machine learning models. As to types of machine learning models, consider, for example, one or more of a support vector machine (SVM) model, a k-nearest neighbors (KNN) model, an ensemble classifier model, a neural network (NN) model, etc. As an example, a machine learning model may be a deep learning model (e.g., deep Boltzmann machine, deep belief network, convolutional neural network, stacked auto-encoder, etc.), an ensemble model (e.g., random forest, gradient boosting machine, bootstrapped aggregation, AdaBoost, stacked generalization, gradient boosted regression tree, etc.), a neural network model (e.g., radial basis function network, perceptron, back-propagation, Hopfield network, etc.), a regularization model (e.g., ridge regression, least absolute shrinkage and selection operator, elastic net, least angle regression), a rule system model (e.g., cubist, one rule, zero rule, repeated incremental pruning to produce error reduction), a regression model (e.g., linear regression, ordinary least squares regression, stepwise regression, multivariate adaptive regression splines, locally estimated scatterplot smoothing, logistic regression, etc.), a Bayesian model (e.g., naïve Bayes, average on-dependence estimators, Bayesian belief network, Gaussian naïve Bayes, multinomial naïve Bayes, Bayesian network), a decision tree model (e.g., classification and regression tree, iterative dichotomiser 3, C4.5, C5.0, chi-squared automatic interaction detection, decision stump, conditional decision tree, M5), a dimensionality reduction model (e.g., principal component analysis, partial least squares regression, Sammon mapping, multidimensional scaling, projection pursuit, principal component regression, partial least squares discriminant analysis, mixture discriminant analysis, quadratic discriminant analysis, regularized discriminant analysis, flexible discriminant analysis, linear discriminant analysis, etc.), an instance model (e.g., k-nearest neighbor, learning vector quantization, self-organizing map, locally weighted learning, etc.), a clustering model (e.g., k-means, k-medians, expectation maximization, hierarchical clustering, etc.), etc.

[0172] As an example, a machine model, which may be a machine learning model (ML model), may be built using a computational framework with a library, a toolbox, etc., such as, for example, those of the MATLAB framework (MathWorks, Inc., Natick, Massachusetts). The MATLAB framework includes a toolbox that provides supervised and unsupervised machine learning algorithms, including support vector machines (SVMs), boosted and bagged decision trees, k-nearest neighbor (KNN), k-means, k-medoids, hierarchical clustering, Gaussian mixture models, and hidden Markov models. Another MATLAB framework toolbox is the Deep Learning Toolbox (DLT), which provides a framework for designing and implementing deep neural networks with algorithms, pretrained models, and apps. The DLT provides convolutional neural networks (ConvNets, CNNs) and long short-term memory (LSTM) networks to perform classification and regression on image, time-series, and text data. The DLT includes features to build network architectures such as generative adversarial networks (GANs) and Siamese networks using custom training loops, shared weights, and automatic differentiation. The DLT provides for model exchange various other frameworks.

[0173] As an example, the TENSORFLOW framework (Google LLC, Mountain View, CA) may be implemented, which is an open-source software library for dataflow programming that includes a symbolic math library, which may be implemented for machine learning applications that may include neural networks. As an example, the CAFFE framework may be implemented, which is a DL framework developed by Berkeley Al Research (BAIR) (University of California, Berkeley, California). As another example, consider the SCIKIT platform (e.g., scikit-learn), which utilizes the PYTHON programming language. As an example, a framework such as the APOLLO Al framework may be utilized (APOLLO.AI GmbH, Germany). As an example, a framework such as the PYTORCH framework may be utilized (Facebook Al Research Lab (FAIR), Facebook, Inc., Menlo Park, California).

[0174] As an example, a training method may include various actions that may operate on a dataset to train an ML model. As an example, a dataset may be split into training data and test data where test data may provide for evaluation. A method may include cross-validation of parameters and best parameters, which may be provided for model training.

[0175] The TENSORFLOW framework may run on multiple CPUs and GPUS (with optional CUDA (NVIDIA Corp., Santa Clara, California) and SYCL (The Khronos Group Inc., Beaverton, Oregon) extensions for general-purpose computing on graphics processing units (GPUS)). TENSORFLOW is available on 64-bit LINUX, MACOS (Apple Inc., Cupertino, California), WINDOWS (Microsoft Corp., Redmond, Washington), and mobile computing platforms including ANDROID (Google LLC, Mountain View, California) and IOS (Apple Inc.) operating system-based platforms.

[0176] TENSORFLOW computations may be expressed as stateful dataflow graphs; noting that the name TENSORFLOW derives from the operations that such neural networks perform on multidimensional data arrays. Such arrays may be referred to as “tensors”.

[0177] As an example, a device may utilize TENSORFLOW LITE (TFL) or another type of lightweight framework. For example, consider a gateway that may be in the field (e.g., on-site) and that may utilize the TFL and / or one or more other types of lightweight frameworks. The TFL framework is a set of tools that enables on-device machine learning where models may run on mobile, embedded, and IoT devices. The TFL framework is optimized for on-device machine learning, by addressing latency (no round-trip to a server), privacy (no personal data leaves the device), connectivity (Internet connectivity is demanded), size (reduced model and binary size) and power consumption (e.g., efficient inference and a lack of network connections). The TFL framework offers multiple platform support, covering ANDROID and iOS devices, embedded LINUX, and microcontrollers. The TFL framework offers diverse language support includes JAVA, SWIFT, Objective-C, C++, and PYTHON. The TFL framework may provide high performance via hardware acceleration and model optimization.

[0178] FIG. 11 shows an example of a method 1100 that includes an acquisition block 1110 for acquiring magnetometer data using a downhole tool of a drillstring in a borehole, where the borehole includes at least one transition point between a cased portion of the borehole and an uncased portion of the borehole; a selection block 1120 for selecting a number of techniques from a group of techniques implementable using downhole circuitry of the drillstring; an application block 1130 for applying the number of techniques to one or more portions of the magnetometer data to generate a corresponding number of results, where each of the results is indicative of a position of the downhole tool being within the cased portion or the uncased portion; and a control block 1140 for, based on at least two of the results, controlling movement of the drillstring in the borehole. For example, consider controlling the drillstring to drill further into the subsurface environment to lengthen the borehole.

[0179] The method 1100 of FIG. 11 is shown as including various computer-readable storage medium (CRM) blocks 1111, 1121, 1131, and 1141 that may include processor-executable instructions that may instruct a computing system, which may be a control system, to perform one or more of the actions described with respect to the method 1100.

[0180] As shown in the example of FIG. 11, the system 1190 may include one or more computers 1192 that include one or more processors 1193, memory 1194 operatively coupled to at least one of the one or more processors 1193, instructions 1196 that may be, for example, stored in the memory 1194, and one or more interfaces 1195 (e.g., one or more network interfaces and / or other interfaces). As an example, the system 1190 may include one or more processor-readable media that include processor-executable instructions executable by at least one of the one or more processors 1193 to cause the system 1190 to perform actions such as, for example, one or more actions of the method 1100. As an example, the instructions 1196 may include instructions of one or more of the CRM blocks 1111, 1121, 1131, and 1141. The memory 1194 may be or include the one or more processor-readable media where the processor-executable instructions may be or include instructions. As an example, a processor-readable medium may be a computer-readable storage medium that is non-transitory that is not a signal and that is not a carrier wave.

[0181] As an example, the system 1190 may include subsystems. For example, the system 1190 may include a plurality of subsystems that may operate using equipment that is distributed where a subsystem may be referred to as being a system. For example, consider a downhole tool system and a surface system. As an example, operations of the blocks 1110, 1120, and 1130 of the method 1100 may be performed using a downhole tool system. As an example, operations of the block 1140 of the method 1100 may be performed using a downhole tool system (e.g., consider in integrated controller in a drillstring). The method 1100 may be implemented using, for example, a downhole system and / or a surface system, which may be a cloud-based or cloud-coupled system.

[0182] As an example, a method may include acquiring magnetometer data using a downhole tool of a drillstring in a borehole, where the borehole includes at least one transition point between a cased portion of the borehole and an uncased portion of the borehole; selecting a number of techniques from a group of techniques implementable using downhole circuitry of the drillstring; applying the number of techniques to one or more portions of the magnetometer data to generate a corresponding number of results, where each of the results is indicative of a position of the downhole tool being within the cased portion or the uncased portion; and, based on at least two of the results, controlling movement of the drillstring in the borehole. In such an example, the magnetometer data can include magnetometer data acquired during rotation of the downhole tool in the borehole.

[0183] As an example, magnetometer data can include magnetometer data acquired when the downhole tool is not being rotated in the borehole. In such an example, one of a number of techniques may determine that at least a portion of the magnetometer data were acquired when the downhole tool was in the uncased portion of the borehole, at least in part during execution of a steering operation of the drillstring. In such an example, the one of the number of techniques may include a cluster analysis technique.

[0184] As an example, a number of techniques may include one or more of a rate-of-change technique and an eccentricity technique. In such an example, an eccentricity technique may include determining eccentricity of two magnetic vector components of the magnetometer data with respect to an equation for an ellipse.

[0185] As an example, a number of techniques may include a degree of spread from a fitted geometric structure technique. For example, consider a fitted geometric structure technique that may utilize an equation for an ellipse.

[0186] As an example, a number of techniques may include a technique that computes an ideal BT value and compares an actual BT value to the ideal BT value.

[0187] As an example, a method may include determining one of the at least one transition point.

[0188] As an example, a method may include performing the method in real-time (e.g., with a drillstring in a borehole).

[0189] As an example, magnetometer data can include a number of datapoints according to a datapoint threshold. For example, consider a datapoint threshold that is approximately 300 datapoints.

[0190] As an example, magnetometer data may be acquired during rotation of a drillstring in a borehole and translation of the drillstring in the borehole. In such an example, a drillstring may be translated in a borehole at a tripping rate, for example, where the tripping rate depends on connection times for making connections between stands of drillpipe that form the drillstring. As an example, a drillstring may be translated in a borehole at a rate of penetration, for example, where the rate of penetration depends on breaking rock at an end of the borehole to lengthen the borehole.

[0191] As an example, a method may include filtering magnetometer data based at least in part on results.

[0192] As an example, a method may include combining results according to two or more permutations of a number of techniques.

[0193] As an example, a method may include determining an uncertainty of a combination of results for two or more techniques.

[0194] As an example, a method may include controlling movement of a drillstring in a borehole that includes steering the drillstring for directional drilling that lengthens the borehole.

[0195] As an example, controlling movement of a drillstring in a borehole may include controlling the drillstring with respect to mud dynamics. In such an example, the mud dynamics correspond to swab or surge. As an example, swab and / or surge may depend on where a drillstring is with respect to a cased portion or an uncased portion of a borehole. For example, dynamics of mud and drillstring interactions may differ when a drillstring is entirely or predominantly within a cased portion when compared to the drillstring being more so in an uncased portion.

[0196] As an example, controlling movement of a drillstring in a borehole may include controlling the movement with respect to identification of one of at least one transition point (e.g., a transition point between cased and uncased portions of a borehole).

[0197] As an example, a system can include a processor; memory accessible to the processor; and processor-executable instructions stored in the memory and executable by the processor to instruct the system to: acquire magnetometer data using a downhole tool of a drillstring in a borehole, where the borehole includes at least one transition point between a cased portion of the borehole and an uncased portion of the borehole; select a number of techniques from a group of techniques implementable using downhole circuitry of the drillstring; apply the number of techniques to one or more portions of the magnetometer data to generate a corresponding number of results, where each of the results is indicative of a position of the downhole tool being within the cased portion or the uncased portion; and, based on at least two of the results, control movement of the drillstring in the borehole.

[0198] As an example, one or more non-transitory computer-readable storage media may include processor-executable instructions executable to instruct a processor to: acquire magnetometer data using a downhole tool of a drillstring in a borehole, where the borehole includes at least one transition point between a cased portion of the borehole and an uncased portion of the borehole; select a number of techniques from a group of techniques implementable using downhole circuitry of the drillstring; apply the number of techniques to one or more portions of the magnetometer data to generate a corresponding number of results, where each of the results is indicative of a position of the downhole tool being within the cased portion or the uncased portion; and, based on at least two of the results, control movement of the drillstring in the borehole.

[0199] As an example, one or more computer-readable storage media may include processor-executable instructions to instruct a computing system to perform one or more methods. In such an example, the one or more computer-readable storage media may be a program product (e.g., a computer program product, a computer system program product, etc.).

[0200] In some embodiments, a method or methods may be executed by a computing system. FIG. 12 shows an example of a system 1200 that may include one or more computing systems 1201-1, 1201-2, 1201-3 and 1201-4, which may be operatively coupled via one or more networks 1209, which may include wired and / or wireless networks.

[0201] As an example, a system may include an individual computer system or an arrangement of distributed computer systems. In the example of FIG. 12, the computer system 1201-1 may include one or more sets of instructions 1202, which may be or include processor-executable instructions, for example, executable to perform various tasks (e.g., receiving information, requesting information, processing information, simulation, outputting information, etc.).

[0202] As an example, a set of instructions may be executed independently, or in coordination with, one or more processors 1204, which is (or are) operatively coupled to one or more storage media 1206 (e.g., via wire, wirelessly, etc.). As an example, one or more of the one or more processors 1204 may be operatively coupled to at least one of one or more network interface 1207. In such an example, the computer system 1201-1 may transmit and / or receive information, for example, via the one or more networks 1209 (e.g., consider one or more of the Internet, a private network, a cellular network, a satellite network, etc.). As shown, one or more other components 1208 may be included.

[0203] As an example, the computer system 1201-1 may receive from and / or transmit information to one or more other devices, which may be or include, for example, one or more of the computer systems 1201-2, etc. A device may be located in a physical location that differs from that of the computer system 1201-1. As an example, a location may be, for example, a processing facility location, a data center location (e.g., server farm, etc.), a rig location, a wellsite location, a downhole location, etc.

[0204] As an example, a processor may be or include a microprocessor, microcontroller, processor component or subsystem, programmable integrated circuit, programmable gate array, or another control or computing device.

[0205] As an example, the storage media 1206 may be implemented as one or more computer-readable or machine-readable storage media. As an example, storage may be distributed within and / or across multiple internal and / or external enclosures of a computing system and / or additional computing systems.

[0206] As an example, a storage medium or storage media may include one or more different forms of memory including semiconductor memory devices such as dynamic or static random access memories (DRAMs or SRAMs), erasable and programmable read-only memories (EPROMs), electrically erasable and programmable read-only memories (EEPROMs) and flash memories, magnetic disks such as fixed, floppy and removable disks, other magnetic media including tape, optical media such as compact disks (CDs) or digital video disks (DVDs), BLUERAY disks, or other types of optical storage, or other types of storage devices.

[0207] As an example, a storage medium or media may be located in a machine running machine-readable instructions, or located at a remote site from which machine-readable instructions may be downloaded over a network for execution.

[0208] As an example, various components of a system such as, for example, a computer system, may be implemented in hardware, software, or a combination of both hardware and software (e.g., including firmware), including one or more signal processing and / or application specific integrated circuits.

[0209] As an example, a system may include a processing apparatus that may be or include a general-purpose processors or application specific chips (e.g., or chipsets), such as ASICs, FPGAs, PLDs, or other appropriate devices.

[0210] As an example, a device may be a mobile device that includes one or more network interfaces for communication of information. For example, a mobile device may include a wireless network interface (e.g., operable via IEEE 802.11, ETSI GSM, BLUETOOTH, satellite, etc.). As an example, a mobile device may include components such as a main processor, memory, a display, display graphics circuitry (e.g., optionally including touch and gesture circuitry), a SIM slot, audio / video circuitry, motion processing circuitry (e.g., accelerometer, gyroscope), wireless LAN circuitry, smart card circuitry, transmitter circuitry, GPS circuitry, and a battery. As an example, a mobile device may be configured as a cell phone, a tablet, etc. As an example, a method may be implemented (e.g., wholly or in part) using a mobile device. As an example, a system may include one or more mobile devices.

[0211] As an example, a system may be a distributed environment, for example, a so-called “cloud” environment where various devices, components, etc. interact for purposes of data storage, communications, computing, etc. As an example, a device or a system may include one or more components for communication of information via one or more of the Internet (e.g., where communication occurs via one or more Internet protocols), a cellular network, a satellite network, etc. As an example, a method may be implemented in a distributed environment (e.g., wholly or in part as a cloud-based service).

[0212] As an example, information may be input from a display (e.g., consider a touchscreen), output to a display or both. As an example, information may be output to a projector, a laser device, a printer, etc. such that the information may be viewed. As an example, information may be output stereographically or holographically. As to a printer, consider a 2D or a 3D printer. As an example, a 3D printer may include one or more substances that may be output to construct a 3D object. For example, data may be provided to a 3D printer to construct a 3D representation of a subterranean formation. As an example, layers may be constructed in 3D (e.g., horizons, etc.), geobodies constructed in 3D, etc. As an example, holes, fractures, etc., may be constructed in 3D (e.g., as positive structures, as negative structures, etc.).

[0213] Although only a few examples have been described in detail above, those skilled in the art will readily appreciate that many modifications are possible in the examples. Accordingly, all such modifications are intended to be included within the scope of this disclosure as defined in the following claims. In the claims, means-plus-function clauses are intended to cover the structures described herein as performing the recited function and not only structural equivalents, but also equivalent structures. Thus, although a nail and a screw may not be structural equivalents in that a nail employs a cylindrical surface to secure wooden parts together, whereas a screw employs a helical surface, in the environment of fastening wooden parts, a nail and a screw may be equivalent structures.

Examples

Embodiment Construction

[0018]The following description includes embodiments of the best mode presently contemplated for practicing the described implementations. This description is not to be taken in a limiting sense, but rather is made merely for the purpose of describing the general principles of the implementations. The scope of the described implementations should be ascertained with reference to the issued claims.

[0019]A borehole may be referred to as a wellbore and may include an openhole portion or an uncased portion and / or may include a cased portion. As explained, a borehole may include a transition point between a cased portion and an uncased portion. In various instances, a borehole may include one or more cased portions and one or more uncased portions. As an example, a borehole may be defined by a bore wall that is composed of rock that bounds the borehole, noting that casing may be disposed in a borehole where the casing may act as a fluid barrier and / or as a stabilizer. As an example, a po...

CROSS REFERENCE TO RELATED APPLICATIONS

[0001] This application claims priority to U.S. Provisional Patent Application No. 63 / 763,772, which was filed on Feb. 26, 2025, and is incorporated herein by reference in its entirety.BACKGROUND

[0002] A drillstring may be moved in a borehole for one or more purposes, which may pertain to tripping, drilling, etc. As an example, a borehole may include a transition between a cased portion and an uncased portion. In various instances, knowledge of where a drillstring is with respect to a cased portion, a transition, or an uncased portion may be relevant. For example, data acquired by one or more downhole tools may operate in a manner that may depend on whether or not a casing is present. As an example, various types of data may be relevant to steering a drillstring in a borehole, for example, for directional drilling that lengthens a borehole. As an example, consider geosteering, which may provide for directional control of a drill bit of a drillstring using downhole geological logging measurements, for example, to keep a directional wellbore within a pay zone. In various scenarios, control of a drillstring may be improved upon knowledge of a relationship of the drillstring, or a portion thereof, with respect to a cased portion, a transition point, or an uncased portion of a borehole.SUMMARY

[0003] A method may include acquiring magnetometer data using a downhole tool of a drillstring in a borehole, where the borehole includes at least one transition point between a cased portion of the borehole and an uncased portion of the borehole; selecting a number of techniques from a group of techniques implementable using downhole circuitry of the drillstring; applying the number of techniques to one or more portions of the magnetometer data to generate a corresponding number of results, where each of the results is indicative of a position of the downhole tool being within the cased portion or the uncased portion; and based on at least two of the results, controlling movement of the drillstring in the borehole. A system can include a processor; memory accessible to the processor; and processor-executable instructions stored in the memory and executable by the processor to instruct the system to: acquire magnetometer data using a downhole tool of a drillstring in a borehole, where the borehole includes at least one transition point between a cased portion of the borehole and an uncased portion of the borehole; select a number of techniques from a group of techniques implementable using downhole circuitry of the drillstring; apply the number of techniques to one or more portions of the magnetometer data to generate a corresponding number of results, where each of the results is indicative of a position of the downhole tool being within the cased portion or the uncased portion; and, based on at least two of the results, control movement of the drillstring in the borehole. One or more non-transitory computer-readable storage media may include processor-executable instructions executable to instruct a processor to: acquire magnetometer data using a downhole tool of a drillstring in a borehole, where the borehole includes at least one transition point between a cased portion of the borehole and an uncased portion of the borehole; select a number of techniques from a group of techniques implementable using downhole circuitry of the drillstring; apply the number of techniques to one or more portions of the magnetometer data to generate a corresponding number of results, where each of the results is indicative of a position of the downhole tool being within the cased portion or the uncased portion; and, based on at least two of the results, control movement of the drillstring in the borehole. Various other apparatuses, systems, methods, etc., are also disclosed.

[0004] This summary is provided to introduce a selection of concepts that are further described below in the detailed description. This summary is not intended to identify key or essential features of the claimed subject matter, nor is it intended to be used as an aid in limiting the scope of the claimed subject matter.BRIEF DESCRIPTION OF THE DRAWINGS

[0005] Features and advantages of the described implementations may be more readily understood by reference to the following description taken in conjunction with the accompanying drawings.

[0006] FIG. 1 illustrates examples of equipment in a geologic environment;

[0007] FIG. 2 illustrates an example of a system and examples of types of holes;

[0008] FIG. 3 illustrates an example of a geologic environment with a borehole and an example of a portion of a drillstring that may include various components;

[0009] FIG. 4 illustrates an example of a portion of a drillstring that may include various components;

[0010] FIG. 5 illustrates examples of logs;

[0011] FIG. 6 illustrates an example of a workflow;

[0012] FIG. 7 illustrates an example of a system;

[0013] FIG. 8 illustrates an example of a plot;

[0014] FIG. 9 illustrates examples of plots;

[0015] FIG. 10 illustrates examples of plots;

[0016] FIG. 11 illustrates an example of a method and an example of a system; and

[0017] FIG. 12 illustrates examples of computing and networking equipment.DETAILED DESCRIPTION

[0018] The following description includes embodiments of the best mode presently contemplated for practicing the described implementations. This description is not to be taken in a limiting sense, but rather is made merely for the purpose of describing the general principles of the implementations. The scope of the described implementations should be ascertained with reference to the issued claims.

[0019] A borehole may be referred to as a wellbore and may include an openhole portion or an uncased portion and / or may include a cased portion. As explained, a borehole may include a transition point between a cased portion and an uncased portion. In various instances, a borehole may include one or more cased portions and one or more uncased portions. As an example, a borehole may be defined by a bore wall that is composed of rock that bounds the borehole, noting that casing may be disposed in a borehole where the casing may act as a fluid barrier and / or as a stabilizer. As an example, a portion of casing may include one or more penetrations such that, for example, fluid may move from a formation to a borehole or from a borehole to a formation.

[0020] As an example, casing may be metallic. For example, casing may be manufactured from carbon steel that is heat-treated to varying strengths. In various instances, casing may be made of one or more of stainless steel, aluminum, titanium, fiberglass, and one or more other materials. Where casing includes a metal or metals, it may be referred to as metallic casing. As an example, various types of metals may be ferromagnetic or otherwise interact with or interfere with a magnetic field. In various instances, movement of a metallic component, a magnetometer, fluid, etc., may impact a magnetic field. For example, consider movement of aluminum in the presence of a magnetic field whereby the aluminum may generate eddy currents, which may oppose the magnetic field.

[0021] In various instances, casing may be set using cement where cement may be disposed between an outer surface of the casing and bore wall, as may be formed of rock. As an example, cementing may involve preparing and pumping cement into place in borehole. Cementing operations may be undertaken, for example, to seal an annulus after a casing string has been run, to seal a lost circulation zone, to set a plug in an existing well from which to push off with directional tools or to plug a well so that it may be abandoned, etc.

[0022] In various instances, drilling may occur in stages or sections where, for example, a drilled section may be at least in part cased prior to drilling another section. Setting casing, cementing, etc., may be part of one or more completions operations. Completions operations generally provide for preparation of a borehole to function as a completed well. Completions may refer to an assembly of downhole tubulars and equipment that aim to enable safe and efficient production and / or injection of fluid.

[0023] As to a well or a borehole, whether for one or more of exploration, sensing, production, injection or other operation(s), it may be planned. Such a process may be referred to generally as well planning, a process by which a path may be mapped in a geologic environment. Such a path may be referred to as a trajectory, which may include coordinates in a three-dimensional coordinate system where a measure along the trajectory may be a measured depth (MD), a total vertical depth (TVD) or another type of measure.

[0024] As an example, drilling may include using one or more logging tools that may perform one or more logging operations while drilling or otherwise with a drillstring (e.g., while stationary, while tripping in, tripping out, etc.). As an example, drilling or one or more other operations may occur responsive to measurements. For example, a logging while drilling operation may acquire measurements and adjust drilling based at least in part on such measurements. In such an example, adjustments may be made by actuating one or more steering actuators that may provide for orienting a drill bit of a drillstring. As an example, one or more types of measurements may be relevant to control of movement of a drillstring in a borehole, for example, as to drilling, hydrodynamics, positioning, etc.

[0025] FIG. 1 shows an example of a system 100 that includes a workspace framework 110 that may provide for instantiation of, rendering of, interactions with, etc., a graphical user interface (GUI) 120. In the example of FIG. 1, the GUI 120 may include graphical controls for computational frameworks (e.g., applications, etc.) 121, projects 122, visualization features 123, one or more other features 124, data access 125, and data storage 126.

[0026] In the example of FIG. 1, the workspace framework 110 may be tailored to a particular geologic environment such as an example geologic environment 150. For example, the geologic environment 150 may include layers (e.g., stratification) that include a reservoir 151 and that may be intersected by a fault 153. As an example, the geologic environment 150 may be outfitted with a variety of sensors, detectors, actuators, etc. For example, equipment 152 may include communication circuitry to receive and to transmit information with respect to one or more networks 155. Such information may include information associated with downhole equipment 154, which may be equipment to acquire information, to assist with resource recovery, etc. Other equipment 156 may be located remote from a wellsite and include sensing, detecting, emitting or other circuitry. Such equipment may include storage and communication circuitry to store and to communicate data, instructions, etc. As an example, one or more satellites may be provided for purposes of communications, data acquisition, etc. For example, FIG. 1 shows a satellite 170 in communication with the network 155 that may be configured for communications, noting that the satellite may additionally or alternatively include circuitry for imagery (e.g., spatial, spectral, temporal, radiometric, etc.).

[0027] FIG. 1 also shows the geologic environment 150 as optionally including equipment 157 and 158 associated with a well that includes a substantially horizontal portion that may intersect with one or more fractures 159. For example, consider a well in a shale formation that may include natural fractures, artificial fractures (e.g., hydraulic fractures) or a combination of natural and artificial fractures. As an example, a well may be drilled for a reservoir that is laterally extensive. In such an example, lateral variations in properties, stresses, etc. may exist where an assessment of such variations may assist with planning, operations, etc. to develop a laterally extensive reservoir (e.g., via fracturing, injecting, extracting, etc.). As an example, the equipment 157 and / or 158 may include components, a system, systems, etc. for fracturing, seismic sensing, analysis of seismic data, assessment of one or more fractures, etc.

[0028] In the example of FIG. 1, the GUI 120 shows some examples of computational frameworks, including the DRILLPLAN, DRILLOPS, PETREL, TECHLOG, PETROMOD, ECLIPSE, PIPESIM, and INTERSECT frameworks (SLB, Houston, Texas).

[0029] The DRILLPLAN framework provides for digital well construction planning and includes features for automation of repetitive tasks and validation workflows, enabling improved quality drilling programs (e.g., digital drilling plans, etc.) to be produced quickly with assured coherency.

[0030] The DRILLOPS framework may execute a digital drilling plan and ensures plan adherence, while delivering goal-based automation. The DRILLOPS framework may generate activity plans automatically individual operations, whether they are monitored and / or controlled on the rig or in town. Automation may utilize data analysis and learning systems to assist and optimize tasks, such as, for example, setting ROP to drilling a stand. A preset menu of automatable drilling tasks may be rendered, and, using data analysis and models, a plan may be executed in a manner to achieve a specified goal, where, for example, measurements may be utilized for calibration. The DRILLOPS framework provides flexibility to modify and replan activities dynamically, for example, based on a live appraisal of various factors (e.g., equipment, personnel, and supplies). Well construction activities (e.g., tripping, drilling, cementing, etc.) may be continually monitored and dynamically updated using feedback from operational activities. The DRILLOPS framework may provide for various levels of automation based on planning and / or re-planning (e.g., via the DRILLPLAN framework), feedback, etc.

[0031] The PETREL framework may be part of the DELFI environment for utilization in geosciences and geoengineering, for example, to analyze subsurface data from exploration to production of fluid from a reservoir. The DELFI cognitive exploration and production (E&P) environment (SLB, Houston, Texas), referred to herein as the DELFI environment or DELFI framework, is a secure, cognitive, cloud-based collaborative environment that integrates data and workflows with digital technologies, such as artificial intelligence and machine learning.

[0032] The PETREL framework provides components that allow for optimization of various exploration, development and production operations. The PETREL framework includes seismic to simulation software components that may output information for use in increasing reservoir performance, for example, by improving asset team productivity. Through use of such a framework, various professionals (e.g., geophysicists, geologists, and reservoir engineers) may develop collaborative workflows and integrate operations to streamline processes (e.g., with respect to one or more geologic environments, etc.). Such a framework may be considered an application (e.g., executable using one or more devices) and may be considered a data-driven application (e.g., where data is input for purposes of modeling, simulating, etc.).

[0033] The TECHLOG framework may handle and process field and laboratory data for a variety of geologic environments (e.g., deepwater exploration, shale, etc.). The TECHLOG framework may structure wellbore data for analyses, planning, etc.

[0034] The PETROMOD framework provides petroleum systems modeling capabilities that may combine one or more of seismic, well, and geological information to model the evolution of a sedimentary basin. The PETROMOD framework may predict if, and how, a reservoir has been charged with hydrocarbons, including the source and timing of hydrocarbon generation, migration routes, quantities, and hydrocarbon type in the subsurface or at surface conditions.

[0035] The ECLIPSE framework provides a reservoir simulator (e.g., as a computational framework) with numerical solutions for fast and accurate prediction of dynamic behavior for various types of reservoirs and development schemes.

[0036] The INTERSECT framework provides a high-resolution reservoir simulator for simulation of detailed geological features and quantification of uncertainties, for example, by creating accurate production scenarios and, with the integration of precise models of the surface facilities and field operations, the INTERSECT framework may produce reliable results, which may be continuously updated by real-time data exchanges (e.g., from one or more types of data acquisition equipment in the field that may acquire data during one or more types of field operations, etc.). The INTERSECT framework may provide completion configurations for complex wells where such configurations may be built in the field, may provide detailed enhanced-oil-recovery (EOR) formulations where such formulations may be implemented in the field, may analyze application of steam injection and other thermal EOR techniques for implementation in the field, advanced production controls in terms of reservoir coupling and flexible field management, and flexibility to script customized solutions for improved modeling and field management control. The INTERSECT framework, as with the other example frameworks, may be utilized as part of the DELFI environment, for example, for rapid simulation of multiple concurrent cases. For example, a workflow may utilize one or more of the DELFI environment on demand reservoir simulation features.

[0037] The aforementioned DELFI environment provides various features for workflows as to subsurface analysis, planning, construction and production, for example, as illustrated in the workspace framework 110. As shown in FIG. 1, outputs from the workspace framework 110 may be utilized for directing, controlling, etc., one or more processes in the geologic environment 150 and, feedback 160, may be received via one or more interfaces in one or more forms (e.g., acquired data as to operational conditions, equipment conditions, environment conditions, etc.).

[0038] As an example, a workflow may progress to a geology and geophysics (“G&G”) service provider, which may generate a well trajectory, which may involve execution of one or more G&G frameworks (e.g., consider the PETREL framework, etc.).

[0039] In the example of FIG. 1, the visualization features 123 may be implemented via the workspace framework 110, for example, to perform tasks as associated with one or more of subsurface regions, planning operations, constructing wells and / or surface fluid networks, and producing from a reservoir.

[0040] As an example, a visualization process may implement one or more of various features that may be suitable for one or more web applications. For example, a template may involve use of the JAVASCRIPT object notation format (JSON) and / or one or more other languages / formats. As an example, a framework may include one or more converters. For example, consider a JSON to PYTHON converter and / or a PYTHON to JSON converter. Such an approach may provide for compatibility of devices, frameworks, etc., with respect to one or more sets of instructions.

[0041] As an example, visualization features may provide for visualization of various earth models, properties, etc., in one or more dimensions. As an example, visualization features may provide for rendering of information in multiple dimensions, which may optionally include multiple resolution rendering. In such an example, information being rendered may be associated with one or more frameworks and / or one or more data stores. As an example, visualization features may include one or more control features for control of equipment, which may include, for example, field equipment that may perform one or more field operations. As an example, a workflow may utilize one or more frameworks to generate information that may be utilized to control one or more types of field equipment (e.g., drilling equipment, wireline equipment, fracturing equipment, etc.).

[0042] As to a reservoir model that may be suitable for utilization by a simulator, consider acquisition of seismic data as acquired via reflection seismology, which finds use in geophysics, for example, to estimate properties of subsurface formations. As an example, reflection seismology may provide seismic data representing waves of elastic energy (e.g., as transmitted by P-waves and S-waves, in a frequency range of approximately 1 Hz to approximately 100 Hz). Seismic data may be processed and interpreted, for example, to understand better composition, fluid content, extent and geometry of subsurface rocks. Such interpretation results may be utilized to plan, simulate, perform, etc., one or more operations for production of fluid from a reservoir (e.g., reservoir rock, etc.).

[0043] As an example, a model may be a simulated version of a geologic environment. As an example, a simulator may include features for simulating physical phenomena in a geologic environment based at least in part on a model or models. A simulator, such as a reservoir simulator, may simulate fluid flow in a geologic environment based at least in part on a model that may be generated via a framework that receives seismic data. A simulator may be a computerized system (e.g., a computing system) that may execute instructions using one or more processors to solve a system of equations that describe physical phenomena subject to various constraints. In such an example, the system of equations may be spatially defined (e.g., numerically discretized) according to a spatial model that that includes layers of rock, geobodies, etc., that have corresponding positions that may be based on interpretation of seismic and / or other data. A spatial model may be a cell-based model where cells are defined by a grid (e.g., a mesh). A cell in a cell-based model may represent a physical area or volume in a geologic environment where the cell may be assigned physical properties (e.g., permeability, fluid properties, etc.) that may be germane to one or more physical phenomena (e.g., fluid volume, fluid flow, pressure, etc.). A reservoir simulation model may be a spatial model that may be cell-based.

[0044] While several simulators are illustrated in the example of FIG. 1, one or more other simulators may be utilized, additionally or alternatively. For example, consider the VISAGE geomechanics simulator (SLB, Houston Texas) or the PIPESIM network simulator (SLB, Houston Texas), etc.

[0045] As an example, a workflow may utilize one or more types of data for one or more processes (e.g., stratigraphic modeling, basin modeling, completion designs, drilling, production, injection, etc.). As an example, one or more tools may provide data that may be used in a workflow or workflows that may implement one or more frameworks (e.g., PETREL, TECHLOG, PETROMOD, ECLIPSE, etc.).

[0046] In the example of FIG. 1, drilling may be performed in the geologic environment 150, for example, to access the reservoir 151, which may be accessed from land or offshore. In FIG. 1, the downhole equipment 154 may be, for example, part of a bottom hole assembly (BHA). The BHA may be used to drill a well. The downhole equipment 154 may communicate information to equipment at the surface, and may receive instructions and information from the equipment at the surface. During a well construction process, a variety of operations (such as cementing, wireline evaluation, testing, etc.) may be conducted. In such embodiments, data collected by tools and sensors and used for reasons such as reservoir characterization may be collected and transmitted.

[0047] A well may include a substantially horizontal portion (e.g., lateral portion) that may intersect with one or more fractures. For example, a well in a shale formation may pass through natural fractures, artificial fractures (e.g., hydraulic fractures), or a combination thereof. Such a well may be constructed using directional drilling techniques as described herein. However, these same techniques may be used in connection with other types of directional wells (such as slant wells, S-shaped wells, deep inclined wells, and others) and are not limited to horizontal wells.

[0048] As an example, a platform, such as, for example, the LUMI platform (SLB, Houston, Texas) may be utilized. The LUMI platform includes features that provide for artificial intelligence solutions as may be integrated with data management capabilities. The LUMI platform provides for flexible deployment options and an open, secure, and modular architecture, for example, to empower data-driven decision-making. The LUMI platform is operable with the DELFI environment and, hence, one or more of various frameworks. While various platforms, environments, frameworks, libraries, etc., are mentioned, a framework may be operable in an agnostic manner, for example, to be compatible with one or more other platforms, environments, frameworks, libraries, technologies, etc.

[0049] FIG. 2 shows an example of a wellsite system 200 (e.g., at a wellsite that may be onshore or offshore). As shown, the wellsite system 200 may include a mud tank 201 for holding mud and other material (e.g., where mud may be a drilling fluid that may help to transport cuttings, etc.), a suction line 203 that serves as an inlet to a mud pump 204 for pumping mud from the mud tank 201 such that mud flows to a vibrating hose 206, a drawworks 207 for winching drill line or drill lines 212, a standpipe 208 that receives mud from the vibrating hose 206, a kelly hose 209 that receives mud from the standpipe 208, a gooseneck or goosenecks 210, a traveling block 211, a crown block 213 for carrying the traveling block 211 via the drill line or drill lines 212 (see, e.g., the crown block 173 of FIG. 1), a derrick 214 (see, e.g., the derrick 172 of FIG. 1), a kelly 218 or a top drive 240, a kelly drive bushing 219, a rotary table 220, a drill floor 221, a bell nipple 222, one or more blowout preventors (BOPs) 223, a drillstring 225, a drill bit 226, a casing head 227 and a flow pipe 228 that carries mud and other material to, for example, the mud tank 201.

[0050] In the example system of FIG. 2, a borehole 232 is formed in subsurface formations 230 by rotary drilling; noting that various example embodiments may also use directional drilling or one or more other types of drilling.

[0051] As shown in the example of FIG. 2, the drillstring 225 is suspended within the borehole 232 and has a drillstring assembly 250 that includes the drill bit 226 at its lower end. As an example, the drillstring assembly 250 may be a bottom hole assembly (BHA).

[0052] The wellsite system 200 may provide for operation of the drillstring 225 and other operations. As shown, the wellsite system 200 includes the platform 215 and the derrick 214 positioned over the borehole 232. As mentioned, the wellsite system 200 may include the rotary table 220 where the drillstring 225 passes through an opening in the rotary table 220.

[0053] As shown in the example of FIG. 2, the wellsite system 200 may include the kelly 218 and associated components, etc., or a top drive 240 and associated components. As to a kelly example, the kelly 218 may be a square or hexagonal metal / alloy bar with a hole drilled therein that serves as a mud flow path. The kelly 218 may be used to transmit rotary motion from the rotary table 220 via the kelly drive bushing 219 to the drillstring 225, while allowing the drillstring 225 to be lowered or raised during rotation. The kelly 218 may pass through the kelly drive bushing 219, which may be driven by the rotary table 220. As an example, the rotary table 220 may include a master bushing that operatively couples to the kelly drive bushing 219 such that rotation of the rotary table 220 may turn the kelly drive bushing 219 and hence the kelly 218. The kelly drive bushing 219 may include an inside profile matching an outside profile (e.g., square, hexagonal, etc.) of the kelly 218; however, with slightly larger dimensions so that the kelly 218 may freely move up and down inside the kelly drive bushing 219.

[0054] As to a top drive example, the top drive 240 may provide functions performed by a kelly and a rotary table. The top drive 240 may turn the drillstring 225. As an example, the top drive 240 may include one or more motors (e.g., electric and / or hydraulic) connected with appropriate gearing to a short section of pipe called a quill, that in turn may be screwed into a saver sub or the drillstring 225 itself. The top drive 240 may be suspended from the traveling block 211, so the rotary mechanism is free to travel up and down the derrick 214. As an example, a top drive 240 may allow for drilling to be performed with more joint stands than a kelly / rotary table approach.

[0055] In the example of FIG. 2, the mud tank 201 may hold mud, which may be one or more types of drilling fluids. As an example, a wellbore may be drilled to produce fluid, inject fluid or both (e.g., hydrocarbons, minerals, water, etc.).

[0056] In the example of FIG. 2, the drillstring 225 (e.g., including one or more downhole tools) may be composed of a series of pipes threadably connected together to form a long tube with the drill bit 226 at the lower end thereof. As the drillstring 225 is advanced into a wellbore for drilling, at some point in time prior to or coincident with drilling, the mud may be pumped by the pump 204 from the mud tank 201 (e.g., or other source) via the lines 206, 208 and 209 to a port of the kelly 218 or, for example, to a port of the top drive 240. The mud may then flow via a passage (e.g., or passages) in the drillstring 225 and out of ports located on the drill bit 226 (see, e.g., a directional arrow). As the mud exits the drillstring 225 via ports in the drill bit 226, it may then circulate upwardly through an annular region between an outer surface(s) of the drillstring 225 and surrounding wall(s) (e.g., open borehole, casing, etc.), as indicated by directional arrows. In such a manner, the mud lubricates the drill bit 226 and carries heat energy (e.g., frictional or other energy) and formation cuttings to the surface where the mud (e.g., and cuttings) may be returned to the mud tank 201, for example, for recirculation (e.g., with processing to remove cuttings, etc.).

[0057] The mud pumped by the pump 204 into the drillstring 225 may, after exiting the drillstring 225, form a mudcake that lines the wellbore which, among other functions, may reduce friction between the drillstring 225 and surrounding wall(s) (e.g., borehole, casing, etc.). A reduction in friction may facilitate advancing or retracting the drillstring 225. During a drilling operation, the entire drillstring 225 may be pulled from a wellbore and optionally replaced, for example, with a new or sharpened drill bit, a smaller diameter drillstring, etc. As mentioned, the act of pulling a drillstring out of a hole or replacing it in a hole is referred to as tripping. A trip may be referred to as an upward trip or an outward trip or as a downward trip or an inward trip depending on trip direction.

[0058] As an example, consider a downward trip where upon arrival of the drill bit 226 of the drillstring 225 at a bottom of a wellbore, pumping of the mud commences to lubricate the drill bit 226 for purposes of drilling to enlarge the wellbore. As mentioned, the mud may be pumped by the pump 204 into a passage of the drillstring 225 and, upon filling of the passage, the mud may be used as a transmission medium to transmit energy, for example, energy that may encode information as in mud-pulse telemetry.

[0059] As an example, mud-pulse telemetry equipment may include a downhole device configured to effect changes in pressure in the mud to create an acoustic wave or waves upon which information may modulated. In such an example, information from downhole equipment (e.g., one or more components of the drillstring 225) may be transmitted uphole to an uphole device, which may relay such information to other equipment for processing, control, etc.

[0060] As an example, telemetry equipment may operate via transmission of energy via the drillstring 225 itself. For example, consider a signal generator that imparts coded energy signals to the drillstring 225 and repeaters that may receive such energy and repeat it to further transmit the coded energy signals (e.g., information, etc.).

[0061] As an example, the drillstring 225 may be fitted with telemetry equipment 252 that includes a rotatable drive shaft, a turbine impeller mechanically coupled to the drive shaft such that the mud may cause the turbine impeller to rotate, a modulator rotor mechanically coupled to the drive shaft such that rotation of the turbine impeller causes said modulator rotor to rotate, a modulator stator mounted adjacent to or proximate to the modulator rotor such that rotation of the modulator rotor relative to the modulator stator creates pressure pulses in the mud, and a controllable brake for selectively braking rotation of the modulator rotor to modulate pressure pulses. In such example, an alternator may be coupled to the aforementioned drive shaft where the alternator includes at least one stator winding electrically coupled to a control circuit to selectively short the at least one stator winding to electromagnetically brake the alternator and thereby selectively brake rotation of the modulator rotor to modulate the pressure pulses in the mud.

[0062] In the example of FIG. 2, an uphole control and / or data acquisition system 262 may include circuitry to sense pressure pulses generated by telemetry equipment 252 and, for example, communicate sensed pressure pulses or information derived therefrom for process, control, etc.

[0063] The assembly 250 of the illustrated example includes a logging-while-drilling (LWD) module 254, a measurement-while-drilling (MWD) module 256, an optional module 258, a rotary-steerable system (RSS) and / or motor 260, and the drill bit 226. Such components or modules may be referred to as tools where a drillstring may include a plurality of tools.

[0064] As to an RSS, it involves technology utilized for direction drilling. Directional drilling involves drilling into the Earth to form a deviated bore such that the trajectory of the bore is not vertical; rather, the trajectory deviates from vertical along one or more portions of the bore. As an example, consider a target that is located at a lateral distance from a surface location where a rig may be stationed. In such an example, drilling may commence with a vertical portion and then deviate from vertical such that the bore is aimed at the target and, eventually, reaches the target. Directional drilling may be implemented where a target may be inaccessible from a vertical location at the surface of the Earth, where material exists in the Earth that may impede drilling or otherwise be detrimental (e.g., consider a salt dome, etc.), where a formation is laterally extensive (e.g., consider a relatively thin yet laterally extensive reservoir), where multiple bores are to be drilled from a single surface bore, where a relief well is desired, etc.

[0065] One approach to directional drilling involves a mud motor; noting that a mud motor may present some challenges depending on factors such as rate of penetration (ROP), transferring weight to a bit (e.g., weight on bit, WOB) due to friction, etc. A mud motor may be a positive displacement motor (PDM) that operates to drive a bit during directional drilling. A PDM operates as drilling fluid is pumped through it where the PDM converts hydraulic power of the drilling fluid into mechanical power to cause the bit to rotate. A PDM may operate in a so-called sliding mode, when the drillstring is not rotated from the surface.

[0066] An RSS may drill directionally where there is continuous rotation from surface equipment, which may alleviate the sliding of a steerable motor (e.g., a PDM). An RSS may be deployed when drilling directionally (e.g., deviated, horizontal, or extended-reach wells). An RSS may aim to minimize interaction with a borehole wall, which may help to preserve borehole quality. An RSS may aim to exert a relatively consistent side force akin to stabilizers that rotate with the drillstring or orient the bit in the desired direction while continuously rotating at the same number of rotations per minute as the drillstring.

[0067] The LWD module 254 may be housed in a suitable type of drill collar and may contain one or a plurality of selected types of logging tools (e.g., NMR unit or units, etc.). It will also be understood that one or more LWD and / or MWD modules may be employed at one or more positions. An LWD module may include capabilities for measuring, processing, and storing information, as well as for communicating with the surface equipment. In the illustrated example, the LWD module 254 may include a seismic measuring device (e.g., sonic, etc.), an NMR measuring device, a resistivity measuring device, etc.

[0068] The MWD module 256 may be housed in a suitable type of drill collar and may contain one or more devices for measuring characteristics of the drillstring 225 and the drill bit 226. As an example, the MWD module 256 may include equipment for generating electrical power, for example, to power various components of the drillstring 225. As an example, the MWD module 256 may include the telemetry equipment 252, for example, where the turbine impeller may generate power by flow of the mud; it being understood that other power and / or battery systems may be employed for purposes of powering various components. As an example, the MWD module 256 may include one or more of the following types of measuring devices: a weight-on-bit measuring device, a torque measuring device, a vibration measuring device, a shock measuring device, a stick slip measuring device, a direction measuring device, and an inclination measuring device.

[0069] As an example, one or more measuring devices may be included in a drillstring (e.g., a BHA, etc.) where, for example, measurements may support one or more of geosteering, geostopping, trajectory optimization, etc.

[0070] FIG. 2 also shows some examples of types of holes that may be drilled. For example, consider a slant hole 272, an S-shaped hole 274, a deep inclined hole 276 and a horizontal hole 278.

[0071] As an example, a drilling operation may include directional drilling where, for example, at least a portion of a well includes a curved axis. For example, consider a radius that defines curvature where an inclination with regard to the vertical may vary until reaching an angle between about 30 degrees and about 60 degrees or, for example, an angle to about 90 degrees or possibly greater than about 90 degrees. As an example, a trajectory and / or a drillstring may be characterized in part by a dogleg severity (DLS), which may be a two-dimensional parameter specified in degrees per 30 meters (e.g., or degrees per 100 feet).

[0072] As an example, a directional well may include several shapes where each of the shapes may aim to meet particular operational demands. As an example, a drilling process may be performed on the basis of information as and when it is relayed to a drilling engineer. As an example, inclination and / or direction may be modified based on information received during a drilling process.

[0073] As an example, deviation of a bore may be accomplished in part by use of a downhole motor and / or a turbine. As to a motor, consider a drillstring that may include a positive displacement motor (PDM).

[0074] As an example, a system may be a steerable system and include equipment to perform a method such as geosteering. As mentioned, a steerable system may be or include an RSS. As an example, a steerable system may include a PDM and / or a turbine on a lower part of a drillstring which, just above a drill bit, a bent sub may be mounted. Geosteering equipment of a drillstring may include one or more geosteering actuators that may provide for orienting a drill bit of the drillstring. For example, an actuator that may include a piston that moves a pad for providing a force that may be exerted against a borehole wall thus steering a bottom hole assembly (e.g., orienting a drill bit of the bottom hole assembly). As an example, an actuator may be a bent downhole motor, which may be actuated via one or more processes. As an example, a bent drilling motor may be used with a fixed bend that cannot be varied during normal operation or with a variable bend that, for example, may be varied based on a geosteering command. As an example, for a variable bend drilling motor, one or more actuators may be included that may be configured to create or vary a bend, thereby affecting the steering behavior of the steering system. As an example, an actuator may be a downhole actuator that may adjust orientation downhole and / or an actuator may be a surface actuator that may perform an action uphole (e.g., at surface) to adjust orientation downhole.

[0075] As an example, above a PDM, MWD equipment that provides real time or near real time data of interest (e.g., inclination, direction, pressure, temperature, real weight on the drill bit, torque stress, etc.) and / or LWD equipment may be installed. As to the latter, LWD equipment may make it possible to send to the surface various types of data of interest, including for example, geological data (e.g., gamma ray log, resistivity, density and sonic logs, etc.).

[0076] The coupling of sensors providing information on the course of a well trajectory, in real time or near real time, with, for example, one or more logs characterizing the formations from a geological viewpoint, may allow for implementing a geosteering method. Such a method may include navigating a subsurface environment, for example, to follow a desired route to reach a desired target or targets.

[0077] As an example, a drillstring may include one or more of an azimuthal density neutron (ADN) tool for measuring density and porosity; a MWD tool for measuring inclination, azimuth and shocks; a compensated dual resistivity (CDR) tool for measuring resistivity and gamma ray related phenomena; a combinable magnetic resonance (CMR) tool for measuring properties (e.g., relaxation properties, etc.); one or more variable gauge stabilizers; one or more bend joints; and a geosteering tool, which may include a motor and optionally equipment for measuring and / or responding to one or more of inclination, resistivity and gamma ray related phenomena.

[0078] As an example, a tool such as the ECOSCOPE tool (SLB, Houston, Texas) may be utilized to acquire measurements. Such a tool may include one or more PNGs and associated detectors. Such a tool may include features for one or more of resistivity, neutron porosity, azimuthal gamma ray, density, elemental capture spectroscopy and sigma measurements. For example, consider features for one or more of 2 MHz and 400 kHz propagation resistivity, elemental capture spectroscopy, neutron-gamma density, capture cross section (sigma), azimuthal bulk density, azimuthal photoelectric factor, azimuthal natural gamma ray, density caliper, ultrasonic caliper, annular pressure and temperature while drilling, triaxial shocks and vibration, and near-bit borehole inclination. Such a tool may be operatively coupled to one or more telemetry systems that may provide for real-time acquisition and, for example, real-time decision making, rendering of graphics, etc. As an example, such a tool may be operatively coupled to one or more types of circuitries, which may, for example, perform computations downhole using measurements acquired downhole.

[0079] As an example, a tool such as the PERISCOPE tool (SLB, Houston, Texas) may be utilized to acquire measurements. For example, consider measurements such as resistivity, which may be acquired using one or more types of receivers. As an example, a receiver may be or include an antenna. For example, the PERISCOPE tool may include tilted, axial, and transverse antenna. As an example, data acquired from such a tool may provide for identification of layers, number of layers, position of a layer or layers, within a distance of 1 meter or more (e.g., up to or more than 8 meters).

[0080] As to sigma measurements (e.g., sigma data), sigma is the macroscopic cross section for the absorption of thermal neutrons, or capture cross section, of a volume of matter, measured in capture units (c.u.). A sigma log is the principal output of a pulsed neutron capture log, which may be used for one or more purposes.

[0081] As an example, one or more types of nuclear measurements may be acquired by one or more tools where such nuclear measurements may include one or more of electron density (ρe), hydrogen index (HI), and thermal neutron capture cross section (sigma or Σ).

[0082] As an example, geosteering may include intentional directional control of a wellbore based on results of downhole geological logging measurements in a manner that aims to keep a directional wellbore within a desired region, zone (e.g., a pay zone), etc. As an example, geosteering may include directing a wellbore to keep the wellbore in a particular section of a reservoir, for example, to minimize gas and / or water breakthrough and, for example, to maximize economic production from a well that includes the wellbore.

[0083] Referring again to FIG. 2, the wellsite system 200 may include one or more sensors 264 that are operatively coupled to the control and / or data acquisition system 262. As an example, a sensor or sensors may be at surface locations. As an example, a sensor or sensors may be at downhole locations. As an example, a sensor or sensors may be at one or more remote locations that are not within a distance of the order of about one hundred meters from the wellsite system 200. As an example, a sensor or sensor may be at an offset wellsite where the wellsite system 200 and the offset wellsite are in a common field (e.g., oil and / or gas field).

[0084] As an example, one or more of the sensors 264 may be provided for tracking pipe, tracking movement of at least a portion of a drillstring, etc.

[0085] As an example, the system 200 may include one or more sensors 266 that may sense and / or transmit signals to a fluid conduit such as a drilling fluid conduit (e.g., a drilling mud conduit). For example, in the system 200, the one or more sensors 266 may be operatively coupled to portions of the standpipe 208 through which mud flows. As an example, a downhole tool may generate pulses that may travel through the mud and be sensed by one or more of the one or more sensors 266 (e.g., consider mud-pulse telemetry). In such an example, the downhole tool may include associated circuitry such as, for example, encoding circuitry that may encode signals, for example, to reduce demands as to transmission. As an example, circuitry at the surface may include decoding circuitry to decode encoded information transmitted at least in part via mud-pulse telemetry. As an example, circuitry at the surface may include encoder circuitry and / or decoder circuitry and circuitry downhole may include encoder circuitry and / or decoder circuitry. As an example, the system 200 may include a transmitter that may generate signals that may be transmitted downhole via mud (e.g., drilling fluid) as a transmission medium.

[0086] Analysis of formation information acquired by one or more tools may reveal features such as, for example, vugs, dissolution planes (e.g., dissolution along bedding planes), stress-related features, dip events, etc. As an example, a tool may acquire information that may help to characterize a reservoir, optionally a fractured reservoir where fractures may be natural and / or artificial (e.g., hydraulic fractures). A reservoir may be a porous formation where fluid may be within various pores of the porous formation and amenable to movement (e.g., to produce fluid from the reservoir). As an example, information acquired by a tool or tools may be analyzed using a framework such as the TECHLOG framework (SLB, Houston, Texas). As an example, the TECHLOG framework may be interoperable with one or more other frameworks such as, for example, the PETREL framework (SLB, Houston, Texas). As an example, a computational environment such as, for example, the DELFI environment (SLB, Houston, Texas) may be utilized, which may provide for utilization of the PETREL framework and other frameworks, optionally in interrelated manners.

[0087] FIG. 3 shows an example of a drilling assembly 300 in a geologic environment 301 that includes a borehole 303 where the drilling assembly 300 (e.g., a drillstring) includes a bit 304 and a motor section 310 where the motor section 310 may drive the bit 304 (e.g., cause the bit 304 to rotate and deepen the borehole 303).

[0088] As shown, the motor section 310 may include a dump valve 312, a power section 314, a surface-adjustable bent housing 316, a transmission assembly 318, a bearing section 320 and a drive shaft 322, which may be operatively coupled to a bit such as the bit 304. The motor section 310 of FIG. 3 may be a POWERPAK family motor section (SLB, Houston, Texas) or another type of motor section.

[0089] A power section may convert hydraulic energy from drilling fluid into mechanical power to turn a bit. For example, consider the reverse application of the Moineau pump principle. During operation, drilling fluid may be pumped into a power section at a pressure that causes the rotor to rotate within the stator where the rotational force is transmitted through a transmission shaft and drive shaft to a bit.

[0090] FIG. 3 also shows examples of components 340 such as, for example, sensors 350, circuitry 360 and a geosteering actuator 370. As shown, the sensors 350 may include a conductivity and dielectric sensor 352, a gamma sensor 354 and one or more other sensors 356. As shown, the circuitry 360 may include a processor 362, memory 364 and one or more other types of circuitries 366. As shown, the geosteering actuator 370 may be operatively coupled to the circuitry 360 and the sensors 350. For example, the circuitry 360 may process signals (e.g., measurements or sensor data) of the sensors 350 to generate one or more commands for actuation of the geosteering actuator 370. In the example of FIG. 3, the geosteering actuator 370 may provide for one or more of PDM actuation and bent sub actuation, for example, to orient the drill bit 304.

[0091] FIG. 4 shows an example of a drilling assembly 400 (e.g., a portion of a drillstring) that includes a bit 404 and a rotary steerable system (RSS) 410. As mentioned, an RSS may be utilized for directional drilling, including geosteering. As an example, the RSS 410 may include one or more features of a POWERDRIVE ARCHER RSS (SLB, Houston, Texas).

[0092] FIG. 4 also shows examples of components 440 such as, for example, sensors 450, circuitry 460 and a geosteering actuator 470. As shown, the sensors 450 may include a conductivity and dielectric sensor 452, a gamma sensor 454 and one or more other sensors 456. As shown, the circuitry 460 may include a processor 462, memory 464 and one or more other types of circuitries 466. As shown, the geosteering actuator 470 may be operatively coupled to the circuitry 460 and the sensors 450. For example, the circuitry 460 may process signals (e.g., measurements or sensor data) of the sensors 450 to generate one or more commands for actuation of the geosteering actuator 470. In the example of FIG. 4, the geosteering actuator 470 may provide for RSS actuation, for example, to orient the drill bit 404.

[0093] As an example, the drilling assembly 400 may include one or more of a near-bit continuous inclination and azimuth measurement unit or sub, a near-bit azimuthal gamma ray measurement unit or sub, and one or more other types of measurement units or subs.

[0094] As an example, a drilling assembly may include one or more types of circuitries. For example, consider a processing unit with a processor and associated memory where one or more sensors may generate signals that may be received by the processing unit. In such an example, the processing unit may perform computations that may utilize information in the signals (e.g., measurements, etc.) to generate commands for geosteering. In such an example, a drilling assembly may be capable of performing, at least in part, downhole geosteering according to geosteering commands generated downhole without transmission of information uphole to a controller and subsequent transmission of information downhole to geosteering equipment. In such an example, at least some types of geosteering processes may be performed more rapidly in response to sensor signals. For example, consider sensor signals indicative of one or more of presence of clay, an amount of clay, a type of clay, and a boundary as an interface between layers, where downhole geosteering equipment may act to steer a drill bit based on one or more of such sensor signals.

[0095] As an example, an electromagnetic conductivity measurement tool (ECM tool) may be implemented as a wireline tool and / or implemented as a LWD tool to generate permittivity and conductivity measurements at each frequency for one or more frequencies, which may be interpreted using a petrophysical model. In such an example, output parameters of the model may include water-filled porosity (hence water saturation if the total porosity is known) and water salinity. As an example, parameters that may be output using ECM tool measurements (e.g., induction, propagation, etc.) may include one or more of bulk formation cation exchange capacity (CEC), water saturation (Sw), connate water salinity, Archie cementation exponent and Archie saturation exponent.

[0096] FIG. 5 shows example logs 500 that include various measurements acquired by one or more downhole tools. For example, the logs 500 include spontaneous potential (mV), gamma ray (gAPI), resistivity (ohm.m), neutron porosity (percent), and bulk density (g.cm−3). The gamma ray response (track 1) distinguishes the low gamma ray value of sand from the higher value of shale. The spontaneous potential curve generally follows a trend similar to that of the gamma ray. The next column, referred to as a depth track (track 2), indicates the depth at which measurements have been acquired. Across the sandstone formation, the resistivity measurements (track 3) are noticeably higher in the hydrocarbon zone than in the water-saturated zone in the lower part of the sand. Both neutron porosity and bulk density (track 4) provide measures of porosity. Within the hydrocarbon-bearing zone, the separation of the curves varies depending on the type of fluid encountered.

[0097] As an example, logs may be acquired as to formation parameters versus depth where, from such logs, lithologies may be identified that may differentiate various type of rock. For example, consider differentiating between porous and nonporous rock, which may provide for identification of one or more pay zones in subsurface formations. In a given field or local geological province, certain formations may have distinctive characteristics that appear similar from one well to the next, providing geologists with a basis for locating the depths of various strata in the subsurface. For example, consider identification of formation tops, which may be tracked from logs of one well to logs of another well. In the example of FIG. 5, the logs 500 include variations with respect to shale and sand where a first interface may be referred to as formation top X and a second interface may be referred to as formation top X+1. In such an example, an interface may be referred to as a boundary, which may also be identifiable in one or more other types of data such as, for example, seismic data. As an example, a workflow may include correlation of seismic picks to geologic picks, such as formation tops interpreted from well logs, to improve model building, etc.

[0098] As to resistivity of rock, it is a measure of the degree to which rock may impede the flow of an electric current. As shown, resistivity may be expressed in units of ohm.m, noting that it may be measured in ohm.m2 / m. The reciprocal of resistivity is conductivity, which is typically expressed in terms of millimhos or mmhos. The ability to conduct electrical current is a function of the conductivity of water contained in pore space of rock. Pure water does not conduct electricity; whereas, salt ions found in most formation waters do provide for conduction of electricity. Brine-saturated rocks tend to have high conductivity and low resistivity, which may be seen in the resistivity log data of FIG. 5 at depths about 7,200 feet. Hydrocarbons, which are nonconductive, cause resistivity values to increase as the pore spaces within a rock become more saturated with oil or gas.

[0099] As to spontaneous potential (SP), it is a measurement of voltage difference between a movable electrode in a wellbore and a fixed electrode at the surface. This electrical potential is primarily generated as a result of exchanges of fluids of different salinities (e.g., salinity of drilling fluid and salinity of formation fluid). During the course of drilling, permeable rock within a wellbore may become invaded by drilling mud filtrate where, if the filtrate is less saline than formation fluid, negatively charged chlorine ions from formation water may cause the SP curve to deflect to the left from an arbitrary baseline established across impermeable shale formations. The magnitude of the deflection is influenced by a number of factors, including permeability, porosity, formation water salinity and mud filtrate properties. Permeable formations filled with water that is fresher than the filtrate will cause the curve to deflect to the right. Hence, by the nature of deflections, an SP log may indicate which formations are permeable. A permeable formation with a high resistivity may be more likely to contain hydrocarbons.

[0100] As shown in the logs 500, a gamma ray (GR) log may be included, along with one or more of multiple resistivity logs and porosity readings obtained from density, neutron, and / or sonic logs. As to GR log acquisition, a downhole tool may measure naturally occurring radioactivity from a formation where a GR log may help differentiate non-reservoir rocks (e.g., shales and clays) from reservoir rocks (e.g., sandstone and carbonates). Shales and clays tend to be derived from rocks that tend to contain naturally occurring radioactive elements, primarily potassium, uranium and thorium. As a consequence, shales and clays are more radioactive than clean sandstones and carbonates. Quartz and calcium carbonate produce almost no radiation. A log analysis may look for formations with low background radiation because they may have potential to contain moveable hydrocarbons.

[0101] Various resistivity tools may measure a formation at different depths of investigation (e.g., shallow, medium and deep). A resulting log may present shallow, medium and deep tracks. A shallow curve, charting the smallest radius of investigation, may indicate resistivity of a flushed zone surrounding a borehole; a medium curve may indicate resistivity of an invaded zone; and a deepest curve may indicate resistivity of an uncontaminated zone, which may be presumed to be a true formation resistivity; noting that such a curve may still be affected by the presence of mud filtrate. By evaluating separations between curves at different depths of investigation, an analysis may provide an estimation of a diameter of invasion by mud filtrate and may be able to determine which zones are more permeable than others.

[0102] As to formation bulk density, it provides a measure of porosity. The bulk density of a formation is based on a ratio of a measured interval's mass to its volume. In general, rock porosity tends to be inversely related to rock density. Formation bulk density may be derived from electron density of a formation. Such a measurement may be obtained by a logging device that emits gamma rays into a formation. Gamma rays may collide with electrons in a formation, giving off energy and scattering in a process known as Compton scattering. The number of such collisions is directly related to the number of electrons in a formation. In low-density formations, more of these scattered gamma rays are able to reach a detector than in formations of higher density.

[0103] As hydrogen tends to be a major constituent of both water and hydrocarbons and because water and hydrocarbons concentrate in rock pores, the concentration of hydrogen atoms may be used to determine fluid-filled porosity of a formation. Hydrogen atoms have nearly the same mass as neutrons. Neutron logging tools emit neutrons using a chemical source or an electronic neutron generator. When these neutrons collide with hydrogen atoms in a formation, they lose the maximal energy, slow down and eventually reach a very-low-energy state (e.g., a thermal state). The rate at which neutrons reach the thermal state is proportional to the hydrogen concentration or index (HI). Various neutron porosity tools measure HI, which may be converted to neutron porosity.

[0104] As an example, a sonic log may be used to determine porosity by charting the speed of a compressional sound wave as it travels through a formation. Interval transit time (Δt), measured in microseconds per meter or foot and often referred to as slowness, is the reciprocal of velocity. Lithology and porosity affect Δt. Dense, consolidated formations characterized by compaction at depth generally result in a faster (shorter) Δt while fluid-filled porosity results in a slower (longer) Δt. Measurements may be affected by formation and borehole conditions. In various instances, quality control processes may be performed on data. As an example, gas, fractures and lack of compaction may demand adjustments to be applied to a sonic log. Lithologies affect the density, neutron and sonic logs. Invasion of mud filtrate into porous formations affects resistivity readings, and temperature affects the resistivity of both filtrate and saline formation water.

[0105] As an example, directional drilling may involve drilling a number of different sections such as, for example, a build section, a landing section and a lateral section. In such an example, a build section may be a portion of a directional wellbore curve that may extend from a kick-off point (KOP) to another point. As to a landing section, it may be a portion of a wellbore beyond a build section where steering may be controlled in an effort to hit a target. A landing section may be composed of segments such as, for example, an upper segment, which may be referred to as an approach section, and a lower segment, which may be referred to as a taper section. In the approach section, the magnitude of changes may tend to be greater than in the taper section as the taper section may aim to form a wellbore that smoothly transition at the end of the landing as the drillstring enters a target zone (e.g., a target formation). As to a lateral section, it may be a portion of a wellbore that extends substantially horizontally from an end of a landing taper, out to an end of the wellbore. A course change within a lateral section may affect a reservoir for better or for worse. As an example, a lateral section may be drilled using a BHA, which may include a mud motor, an RSS, etc. In various scenarios, inclination and / or azimuth of a lateral section may be maintained through a combination of sliding and rotating of a drillstring.

[0106] As an example, directional drilling may include geosteering as part of a landing job (e.g., drilling a landing section). In a landing job for a well, estimated well tops in the current well may lack accuracy. For example, estimated well tops may be rough estimates based on data from one or more offset wells as may be visually assessed by one or more individuals. As explained, a drillstring may include one or more logging tools to acquire measurements while drilling (e.g., MWD, LWD, etc.). Thus, when a current well is being drilled, real-time log measurements may be acquired. Where such measurements are available, an assessment may involve performing a comparison of a current well's log data and log data from one or more other wells (e.g., log data from one or more offset wells) to generate a more accurate estimate of one or more well tops. Such an assessment may be referred to as log correlation during geosteering. During directional drilling, accurate estimation of well tops may provide for decision making. For example, consider decision making as to whether drilling has arrived one or more points along a trajectory (e.g., planned trajectory points, safety points, etc.). In various instances, a point may be associated with an operation (e.g., a downhole operation, etc.) that is to be performed. During a landing job, a decision may relate to termination of a landing section or a transition from one landing segment to another.

[0107] As explained, directional drilling may involve performing log correlation visually, for example, using a number of logs rendered to a display. In such an example, one or more well placement engineers may interact with a graphical user interface that may provide for rendering logs to a display and manually adjusting positions of logs with respect to one another, picking well tops, etc.

[0108] As an example, a framework may include one or more components and / or operatively coupled to one or more components for implementing an integrated predictive geosteering workflow. In such an example, components may provide for executing a structural update, a resistivity forward prediction and an uncertainty prediction.

[0109] As an example, a framework may include one or more plug-in components. For example, consider one or more PETREL framework plug-in components. As to the PETREL framework, it may operate in conjunction with one or more plug-ins. For example, a plug-in may instruct an instance of PETREL as to performance of one or more of techniques (e.g., import, export, computation, etc.). As an example, a plug-in may provide for launching one or more components within a PETREL framework environment, for example, executing using local resources and / or executing using remote resources (e.g., consider one or more of a workstation, a networked HPC cluster, a cloud platform, etc.).

[0110] As an example, a workflow may be implemented for execution in real-time using at least in part field data. In such an example, components may be coordinated to expedite execution, for example, by reducing number of calls and responses, logistic waiting times, etc. For example, consider a plug-in that may be a unified plug-in for implementation of sub-workflows in an integrated predictive geosteering workflow (IPG workflow). As an example, a framework may include one or more visualization components. For example, consider a component that may provide for implementing a method that creates visualizations of results from a number of sub-workflows, which may provide for improved interpretations.

[0111] FIG. 6 shows an example of a drillstring 610 with various BHA features and an example of a drillstring 620 with various BHA features. As an example, the drillstrings 610 and 620 may include one or more of the features of the drillstring assembly 250 of FIG. 2. As shown in the examples of FIG. 6, the drillstring 610 includes a drill bit 612 and a group of direction and inclination (D&I) sensors 614 that are positioned relatively close to the drill bit 612 while the drillstring 620 includes a drill bit 622, a group of D&I sensors 624 that are positioned relatively close to the drill bit 622, one or more other D&I sensors 626, a D&I gyroscope sensor 627, and one or more D&I MWD sensors 628. In such examples, the closer a sensor is to a drill bit, in general, the more accurately the sensor may provide an indication of a downhole position of the drill bit, which, as explained, may provide for hole bottom estimation (HBE). As explained with respect to the system 400, the data service 412 may acquire data for one or more purposes, which may include data for utilization by the state estimation component 414, which may provide for HBE.

[0112] As to a gyroscope sensor, consider, as an example, a gyroscope sensor that includes one or more features of the GYROSPHERE tool (SLB, Houston, Texas). As an example, a gyroscope sensor may provide for acquisition of gyro-surveying data in a manner that may help to an ellipse of uncertainty. As an example, a gyroscope sensor may include microelectromechanical systems (MEMS) technology that may utilize the Coriolis effect, for example, consider use of a vibrating structure that may provide for determination of a rate of planetary rotation. As an example, such a rate may be sensor data that may be utilized to determine one or more of inclination, azimuth, and toolface orientation. As an example, a gyroscope sensor may provide for survey data during a connection of drillpipe. For example, a measurement may be taken during a connection where the measurement may be available immediately after mud pumps are on (e.g., making data available more rapidly) due to MEMS technology not having to spin up and stabilize. As an example, two surveys may be performed in the time a non-MEMS gyroscope takes to start up for just one survey. As an example, a gyroscope sensor may be a MEMS technology-based sensor that may handle relatively severe shock and vibration. As an example, a single sensor may be utilized to survey at an inclination, at a depth, and at higher latitudes, without a demand for changing batteries or recalibrating between runs, which may make batch-drilling operations more efficient. As an example, one or more gyroscope sensors may be included on a drillstring. As an example, an RSS tool may include a gyroscope sensor. As an example, a drilling may include a gyroscope sensor in a module or unit that may be assembled on a drillstring (e.g., a tool with a length that makes up part of a length of a drillstring). As an example, an MWD tool may include a gyroscope sensor.

[0113] As an example, an MWD tool may include various sensors for acquiring data, which may include survey data such as, for example, direction and inclination (D&I) data. An MWD tool may be powered electrically using one or more mechanisms. For example, consider a battery, a fluid turbine generator, etc. Where multiple mechanisms are included, they may provide for redundancy and increased up-time. For example, a battery may provide for operation during intermittent drilling-fluid flow conditions. Battery power may also provide for logging during tripping in (running in hole (RIH)) or out of the hole (pulling out of hole (POOH)). As such, an MWD tool on a drillstring may acquire data for the same location multiple times as it passes the location during drilling, RIH, POOH, etc.

[0114] As to sensors, an MWD tool may include directional-sensor technology that may, for example, utilize an array of three orthogonal fluxgate magnetometers and three accelerometers. While standard directional sensors may provide acceptable surveys, in scenarios where uncertainty exists in a bottomhole location, more sophisticated sensor technology may help to reduce such uncertainty. Yet, as explained, even with more sophisticated sensor technology, uncertainty may still exist, which may be exacerbated by recent trends to drill longer and more complex wells. Various types of errors may also exist for MWD measurements, which may include, for example, one or more of sensor error, magnetic interference from the BHA, tool misalignment, and magnetic-field uncertainty.

[0115] As to MWD telemetry, mud-pulse telemetry is a standard method in various commercial MWD and LWD systems, noting that one or more other types of telemetry may be utilized, additionally or alternatively. Demands on telemetry may be imposed by real-time azimuth correction, which involve transmission of raw data to surface. Further, telemetry may introduce uncertainties when compression / decompression are utilized (e.g., with loss or lossless) and general types of transmission errors (e.g., noise, physical events, etc.).

[0116] As to an MWD survey, recordings of MD, inclination, and hole direction may be taken at a survey station where a number of survey stations may be obtained along a path. Such measurements may be used together to calculate 3D coordinates, which may then be presented as a table of numbers called a survey report. Surveying may be performed during a drilling run, while RIH, POOH, after drilling has been completed, etc. An MWD survey of an MWD tool of a drillstring demands that breaking rock with a drill bit of the drillstring is halted (e.g., drilling suspended) such that the MWD tool may remain stationary in an environment with diminished noise to acquire sensor data for the MWD survey. An MWD survey may be utilized for one or more purposes such as, for example, one or more of determining a bottomhole location to monitor reservoir performance, monitoring an actual path to help ensure a target will be reached, orienting deflection tools for navigating paths, reducing risks of intersecting a nearby well, computing the TVD of various formations to allow for geological mapping, evaluation DLS, and fulfilling requirements of regulatory agencies, such as the Minerals Management Service (MMS) in the US. As to the latter, if an ability to survey using an MWD tool on a drillstring becomes impractical or impossible, drilling may be terminated until the issue is resolved, for example, to assure compliance with regulatory requirements, to reduce risk of colliding with another borehole, wellbore, etc.

[0117] Where an RSS tool is utilized, one or more of downlinks and uplinks may be employed. Downlinks may be commands transmitted for receipt by an RSS tool. Such downlinks may employ rotational techniques such as adjusting drillstring RPM as a signal (e.g., via a top drive) that encodes a command and / or flow techniques such as adjusting flow of drilling fluid (e.g., mud) as a signal (e.g., via one or more mud pumps) that encodes a command. As an example, one or more techniques may involve use of a surface listener as a type of equipment that may sense the RPM and / or flow adjustments. For example, a surface listener may sense pressure and then associate sensed pressure data with downlink codes. In such an example, the surface listener may understand and confirm downlinks to an RSS tool (e.g., knowing what commands may have been sent). A surface listener may be helpful in the instance where, for one or more reasons, uplinks are not possible or otherwise unreliable. For example, an uplink may be a signal generated by an RSS tool that is destined for receipt by an MWD tool where the MWD tool may employ mud-pulse telemetry to convey the signal (e.g., or content thereof) to surface.

[0118] As an example, an RSS tool may include sensors that may provide for measurements of one or more of inclination offset to tool bottom, azimuth offset to tool bottom, average gamma ray, gamma ray offset to tool bottom, vibration axial, vibration radial, shock, triaxial shock and vibration axis, magnetic field cone of exclusion, etc. As an example, sensors may include one or more of gyroscopic sensors, accelerometers, magnetometers, gamma ray sensors, shock and vibration sensors, pressure sensors, temperature sensors, etc. As an example, sensors may be arranged as a group or a package. As explained, a sensor or sensors may be positioned along a drillstring, which may be at one or more distances from a drill bit of the drillstring.

[0119] As explained, an RSS tool may include D&I sensors and / or one or more other sensors that acquire data where the data may be stored locally and / or transmitted. As explained, an RSS tool may utilize uplink technology to transmit data from the RSS tool to an uphole MWD tool, as may be located a distance from the RSS tool on a common drillstring.

[0120] As an example, where a mud motor is utilized on a drillstring with an MWD tool and without an RSS tool, data from the MWD tool may be utilized in a mud motor mode. In various instances, a drillstring may include an MWD tool and may include a mud motor and an RSS tool; whereas, in general, a mud motor or an RSS tool will be present for directional drilling.

[0121] As explained, a borehole may have a direction and a borehole bottom (e.g., hole bottom (HB) or bottom of hole (BH)) may have an orientation. For example, consider a borehole orientation that may be described in terms of inclination and azimuth. Inclination generally refers to the vertical angle measured from the down direction where down, horizontal, and up directions have inclinations of 0 degrees, 90 degrees and 180 degrees, respectively. Azimuth generally refers to the horizontal angle measured clockwise from north, which may be a type of “north” or defined “north”. In general, north, east, south and west directions have azimuths of 0 degrees, 90 degrees, 180 degrees and 270 degrees, respectively. In drilling, azimuth may be defined as a compass direction of a directional survey or of a wellbore as planned or measured by a directional survey where, for example, the azimuth may be specified in degrees with respect to a geographic north, a magnetic north pole, or another defined “north”. As an example, an HB may be defined as a flat surface (e.g., a planar surface) with an orientation that may be defined by a vector that points in a direction normal to the flat surface. In such an example, an HB may be defined by a position (e.g., a measured depth) and an orientation (e.g., a direction). As an example, a system may provide for maintaining proper reference to one or more directions (e.g., north, south, east, west, etc.). Maintaining proper reference may facilitate directional drilling in relatively thin layer reservoirs that may have an upper true vertical depth (TVD) limit and a lower TVD limit. Geosteering in such reservoirs may be challenging though improved when a proper reference is maintained (e.g., to assure proper reservoir contact between a borehole and a reservoir). As explained, a system may help to maintain a proper reference through developing a series of estimated HBs (e.g., position and orientation) along a borehole.

[0122] As an example, one or more types of measurements may provide for assessing uncertainty of one or more other types of measurements. For example, temperature may be utilized to assess uncertainty of a sensor with respect to its operational temperature range. In such an example, if a temperature is measured that is outside of an operational temperature range for a sensor, measurements from that sensor may have greater uncertainty.

[0123] As an example, an earth model may provide for pressure and temperature modeling with respect to depth (e.g., true vertical depth (TVD)). In such an example, measured pressure and / or measured temperature may be compared to values, gradients, etc., of an earth model, which may help to increase accuracy of and / or otherwise check a HB position (e.g., an HBE).

[0124] As mentioned, a working plan may be or include a trajectory to construct a path from a current bit location (e.g., a HB position) to a next target location (e.g., a desired HB position). As an example, a framework may include features that may implement an automatic method to estimate the position of a bottom of a hole (BH or HB) during well construction execution. For example, along a BHA, the position of one or more sensors that may be used to estimate a location of a borehole may be within three meters of a drill bit (e.g., less than approximately three meters but greater than approximately 20 cm) or they may be a considerable distance from a drill bit (e.g., more than 3 m, 5 m, 10 m, 30 m, etc.). In such an example, where measurements of sensors are used, some type of predictive model is generally required to estimate the exact, actual location of a bottom of a hole (HB). For example, even when a group of sensors is located within one meter of a drill bit, an estimation or prediction may be required for an HBE. As an example, a framework may include one or more features that may improve HBE where such one or more features may provide for more accurate and automated estimation of the exact, actual location of a bottom of a hole (BH or HB).

[0125] As an example, a framework may include one or more features for optimal filtering that consumes, in real-time (RT), one or more types of downhole information (e.g., D&I, etc.) for providing an estimation of one or more HB parameters, for example, with uncertainties and continuous trajectory interpolation along with extrapolation outputs. In such an example, the framework may provide for estimation of HB position and / or drill bit position during directional drilling activities.

[0126] As mentioned, modern wells may be relatively complex and thereby pose an increased number of risk and reward scenarios for proper planning and execution. As to automation, whether in planning and / or execution, automation may aim to de-skill and de-man a directional drilling process while ensuring efficiency and consistency. For example, with automation, demand for on-site personnel may be lessened (e.g., fewer people) and / or skill level(s) of on-site personnel may be lessened and / or shifted (e.g., shifted to automation oversight versus directional drilling decision making).

[0127] As explained, an autonomous directional drilling (DD) system may aim to achieve one or more goals, for example, through use of an automated directional drilling advisor framework that provides real-time optimal decision-making. As an example, an autonomous DD system may provide for automation levels of various workflows. For example, consider one or more workflows motor control, trajectories, commands and / or downlink recommendations for one or more RSSs. Such an autonomous DD system may be suitable for one or more of multiple types of wells where it may automatically provide, from start to end of a section, at each survey point, an appropriate next sequence of actions.

[0128] FIG. 7 shows an example of a portion of a wellbore 702 (e.g., a borehole) with respect to an r, z coordinate system (e.g., a cylindrical coordinate system) as penetrating a portion of a subterranean formation 710 (e.g., a sedimentary basin, etc.). As shown in the example of FIG. 7, a drillstring 712 may be positioned at least in part in the wellbore 702 where the drillstring 712 may include a tool (or module) 720 (e.g., a measurement tool, a logging tool, etc.) and telemetry equipment 740 (e.g., which may be part of the tool 720 or another tool).

[0129] As shown in the example of FIG. 7, the wellbore 702 includes casings 704-1 and 704-2 having casing shoes 706-1 and 706-2. As shown, cement annuli 703-1 and 703-2 are disposed between the wellbore 702 and the casings 704-1 and 704-2. Cement such as the cement annuli 703-1 and 703-2 can support and protect casings such as the casings 704-1 and 704-2 and when cement is disposed throughout various portions of a wellbore such as the wellbore 702, cement can help achieve zonal isolation.

[0130] In the example of FIG. 7, the wellbore 702 has been drilled in sections or segments beginning with a large diameter section (see, e.g., r1) followed by an intermediate diameter section (see, e.g., r2) and a smaller diameter section (see, e.g., r3). As an example, a large diameter section may be a surface casing section, which may be three or more feet in diameter and extend down several hundred feet to several thousand feet. A surface casing section may aim to prevent washout of loose unconsolidated formations. As to an intermediate casing section, it may aim to isolate and protect high pressure zones, guard against lost circulation zones, etc. As an example, intermediate casing may be set at about 6000 feet and extend lower with one or more intermediate casing portions of decreasing diameter (e.g., in a range from about thirteen to about five inches in diameter). A so-called production casing section may extend below an intermediate casing section and, upon completion, be the longest running section within a wellbore (e.g., a production casing section may be thousands of feet in length). As an example, production casing may be located in a target zone where the casing is perforated for flow of fluid into a lumen of the casing.

[0131] Prior to introducing cement into an annulus between a bore and a casing, calculations may be performed to estimate an amount of cement sufficient to fill the annulus, for example, for purposes of sealing off a casing segment. Accuracy of an estimate as to the amount of cement as well as issues in a process of introducing cement may, for example, result in occasional voids or gaps (e.g., regions where cement is lacking). Depending on the nature of such voids or gaps, casing or borehole integrity may be at risk or compromised. However, where one or more integrity detection techniques can be implemented, it may be possible to detect voids or gaps and call for remedial action, alteration of a plan, etc.

[0132] As an example, equipment may provide for detecting casing magnetic interference in real-time. In such an example, the equipment may include circuitry where such circuitry may provide for generation of data that may be consumed by a computational framework. In such an example, the computational framework may provide for improved control of one or more drilling operations, which may include, for example, one or more of planning, re-planning, hydraulics control, drawworks control, top drive control, steering control, etc.

[0133] As explained, a drillstring may include an MWD tool that may utilize a combination of three orthogonal magnetometers and accelerometers to determine azimuth and inclination of a tool-face (e.g., drill bit tool-face (TF)). As explained, knowledge of azimuth and inclination (AZ and INCL) may provide for proper directional drilling, which may include geosteering. However, as explained, a wellbore may include one or more cased portions where such casing may be metallic. Being metallic, casing may serve as a source of intense magnetic interference to a magnetometer, thus compromising magnetometer performance, readings, etc. For example, magnetic interference from metallic casing may impede a tool's ability to adhere to a planned trajectory of a well. As an example, equipment may be configured to provide for detecting and indicating the presence of metallic casing in real-time. For example, consider a method that may provide for detecting and flagging the presence of metallic casing in real-time by analyzing patterns in tool sensor data as may be acquired and streamed in real-time. In such an example, a framework may provide for issuance of one or more casing-related signals responsive to receipt of tool sensor data as may be acquired and streamed in real-time.

[0134] As to interference, consider how a magnetometer may exhibit relatively erratic behavior when it is within a cased section of a well, surrounded peripherally by metallic casing. In such a scenario, a magnetometer response may be assessed in multiple dimensions, which may include a temporal dimension. For example, consider multiple spatial dimensions and a temporal dimension. As an example, for a given set of magnetometer data, a 3D spatial approach may be taken for a window in time. As an example, a framework may provide for an assessment of erratic behavior in three spatial dimensions of a magnetometer response in one or more cased regions of a wellbore.

[0135] As an example, a framework may provide for assessing a vector sum of radial channels that may show substantially noisy and unreliable readings for a cased region while registering relatively clean, sensible data soon after descending past a cased region into an uncased region. As an example, a framework may provide for acquiring measurements (e.g., observations) from one or more downhole runs and performing one or more analyses as to statistical properties. In such an example, based on such initial observations, analyses on statistical properties may be developed where, for example, one may involve tracking the rate at which values progress, and where, for example, one or more others may be based on circularity of a plot of one or more radial channels.

[0136] As an example, a framework may provide for unsupervised learning. For example, consider an approach whereby data are acquired and processed in an unsupervised manner to generate one or more trained and / or selected models, techniques, etc. As an example, consider a framework that may utilize unsupervised algorithms, and an optimal combination of explored methodologies to enable generation of a reliable prediction. In various example trials, as explained herein, a combined solution approach may provide for quantifying uncertainty of predictions as well as investigation of one or more reasons for one or more underperforming runs.

[0137] In a particular example trial, a test dataset, composed of historical field data, covered a comprehensive expanse of well-trajectory and rig types, from different locations. The performance of various approaches was scored against a label defined by domain knowledge. Each of the various approaches was compared and ranked on the basis of accuracy in predicting the correct label. As explained, as an approach may be for real-time utilization, for example, using circuitry embedded in a drillstring (e.g., a downhole tool or tools), a model-based approach may be tailored to a relatively low-RAM capacity and, for example, adapted on prediction delay.

[0138] As explained herein, a framework may be implemented using downhole circuitry or, for example, downhole and surface circuitry, that can leverage various unique properties of downhole tool data to inform a tool as to when it has left a cased region. In such an example, a tool may provide for conserving various processing functions, energy, data transmissions, etc., for sensor data that have assurances that risk of interference from metallic casing (e.g., noise, erratic data, etc.) is reduced. For example, circuitry of a tool may provide for triggering one or more functions of the circuitry upon an indication that acquired sensor data are relatively clean and free from interference. As an example, a framework may provide for improving one or more ranging systems, imaging processes, etc., that utilize magnetometer data. As an example, a framework may provide for detecting and / or validating a recorded casing shoe-depth. As an example, a framework may provide for improved automation. For example, consider a framework that may provide for improved sensor data that may be more reliable for an automated controller, which may provide for control of one or more types of equipment involved in one or more drilling operations, which may include, for example, one or more of tripping (e.g., in or out), drilling using one or more modes, geosteering, etc. As explained, a framework may provide for improved planning, re-planning, control, etc. As an example, rig automation may be improved via a technique that provides for detection of metallic casing and one or more ends of casing. As explained, various techniques may provide for improved efficiency of one or more directional drilling processes.

[0139] As an example, a system can include circuitry for detecting casing magnetic interference in real-time. As an example, such circuitry may be disposed in a drillstring or, for example, in a drillstring and surface equipment where telemetry is utilized to transmit data from the drillstring to one or more pieces of surface equipment. As explained, telemetry may be utilized to transmit data between downhole tools, from a downhole tool to another downhole tool, and / or from a downhole tool to surface equipment.

[0140] As explained, MWD tools may use a combination of three orthogonal magnetometers and accelerometers to determine azimuth and inclination of a tool-face (TF). As explained, TF may be an angle measured in a plane perpendicular to a drillstring axis that is between a reference direction on the drillstring and a fixed reference. For example, for near-vertical wells, north may be a fixed reference and an angle may be a magnetic toolface. As an example, for more-deviated wells, the top of a borehole may be a fixed reference and an angle may be a gravity toolface, or high side toolface.

[0141] As explained, casing may be metallic and a source of relatively intense magnetic interference to a magnetometer. As explained, a magnetometer is an instrument that includes components and circuitry for measuring strength or direction of the Earth's magnetic field. As an example, a magnetic field may be represented using a vector notation and a coordinate system. For example, consider a Cartesian coordinate system, a cylindrical coordinate system, a spherical coordinate system, etc. As an example, for a Cartesian coordinate system with orthogonal axes, consider x-axis, y-axis, and z-axis, three-axis readings may be defined as Bx, By and Bz. In a cased portion or portions of a borehole, one or more of these readings may be compromised. Where such interference occurs, an MWD tool may be challenged in computing an accurate azimuth value, which, in turn, may impede an ability to adhere to a planned or otherwise desirable trajectory of a borehole.

[0142] As explained, an MWD tool may also include an accelerometer (or accelerometers). As an example, an MWD tool may generate data that includes accelerometer data (e.g., Gx, Gy and Gz) and magnetometer data (Bx, By and Bz). As an example, an MWD tool may also generate temperature data and / or one or more other types of data. As explained, surface equipment may receive and processes MWD data to generate values for one or more of azimuth, inclination, total gravity field, gravity tool face, magnetic tool face, total magnetic tool face, and dip angle. As an example, a framework may provide for generate an indicator, a value, etc., as to a cased portion or cased portions of a borehole, which may include a transition point as to a transition between a cased portion and an uncased portion of a borehole. For example, consider generation of an indicator, a value, etc., as to a casing shoe position (e.g., a casing shoe measured depth, etc.).

[0143] As an example, a framework may provide for utilization of one or more of a number of techniques. For example, consider an approach that implements four different techniques that utilize raw data from a magnetometer (or magnetometers) and analyze patterns that may point to presence of casing. As an example, such a framework may operate by comparing acquired data to what may be expected for ideal conditions. For example, consider an approach that involves analyzing rate-of-change of readings, which may utilize one or more properties of a circle resulting from a plot of Bx versus By (e.g., or other appropriate geometric construct). For example, where a circle is utilized, eccentricity and spread of datapoints may be fit to an equation for an ellipse and, for example, a comparison performed as to a recorded BT value (e.g., a sum of Bx and By) to an ideal, predicted BT value (e.g., a sum of predicted Bx and By or merely a predicted BT).

[0144] As an example, a framework may provide for generating an indicator (e.g., a flag, a trigger, etc.) responsive to the presence of casing in real-time by analyzing three-axis input readings from a magnetometer in an MWD tool. In such an example, a result may be a combination of predictions from four or more separate techniques, as may be developed based on unique properties of input data during cased periods and uncased periods, for example, as a drillstring with an MWD tool is being moved within a borehole.

[0145] As explained, a framework may operate in real-time. To achieve real-time performance, latencies or other types of delays may be minimized, particularly as to circuitry to generate predictions in real-time. As explained, circuitry may be embedded in a drillstring such as within an MWD tool. In various instances, an MWD tool or other tool that includes one or more magnetometers may possess a limited amount of memory (e.g., hardware for storing data, commands, etc.). As an example, a framework may be a computational framework that may be relatively lightweight. As an example, such a framework may provide for generating predictions using a limited amount of information (e.g., data, etc.). As an example, a framework may operate in a manner that is restricted to tool dump data without use of one or more surface channels. As an example, such tool dump data may be data that is amenable to reading at surface upon pulling a drillstring out of a borehole and / or data that may be amenable to transmission via telemetry (e.g., mud-pulse telemetry, etc.).

[0146] As an example, a method may involve a magnetometer acquiring readings determining orientation of a tool-face (or toolface or TF) with respect to the Earth's magnetic field in three dimensions, Bx, By and Bz. These readings may be quite susceptible to magnetic interference and give noisy outputs when in close proximity to casing. As an example, noise may be characterized together with signal (e.g., signal-to-noise ratio (SNR), etc.) and / or via one or more other techniques, metrics, etc.

[0147] As explained, a borehole may be considered to be, on an incremental basis, cylindrical. As explained, for deviated boreholes, direction, orientation, etc., of the cylinder changes with respect to depth for at least a portion over a total measured depth. For example, for a vertical portion of a borehole hole, a cylinder may be representative of that vertical portion; whereas, for a dog-leg, multiple cylindrical intervals may be utilized. And, for a horizontal portion, one or more cylindrical intervales may be utilized, the number of which may depend on how a reservoir region varies with spatially in a subsurface environment.

[0148] Given a cylindrical representation of a portion of a borehole and a Cartesian coordinate system representation of a magnetometer vector, a z-axis may be considered aligned with a longitudinal axis of the borehole; whereas, an x-axis and a y-axis may be considered to be planar where the z-axis is normal to a plane defined by the x-axis and y-axis. With respect to a cylindrical borehole, the plane defined by the x-axis and y-axis may be considered to be a radial plane where, for example, Bx and By represent radial components of the magnetometer vector.

[0149] As an example, a framework may consider that the radial axes (Bx and By) suffer effects of interference from casing to a greater extent that the longitudinal axis (Bz), where the radial axes values may exhibit relatively erratic jumps in readings in the presence of casing. As a magnetometer exits a cased portion of a borehole, such behavior may cease. For example, consider an MWD tool descending in a borehole where once the MWD tool descends out of a cased region of the borehole, erratic nature of radial axes readings dissipates. As an example, a technique may involve utilization of a vector sum. For example, a vector sum of Bx and By, denoted BT, may give a thorough outlook of this effect on these axes through use of BT as a single value (e.g., a single metric to indicate a transition from a cased region to an uncased region or vice versa).

[0150] As explained, during drilling a drillstring or at least a portion thereof rotates. For example, during a sliding mode using a mud motor to rotate a drill bit, a drillstring may be oscillated at surface and / or remain stationary at surface; whereas, in a rotary mode, a drillstring is rotated using surface equipment (e.g., a top drive, a rotary table, etc.). As an example, an MWD tool may be located on a portion of a drillstring such as on a BHA, which may include a mud motor. Depending on location of the MWD tool, it may or may not rotate responsive to rotation of a mud motor. For example, if the MWD tool is uphole from a mud motor, it may rotate responsive to surface driven rotation of a drillstring but not responsive to mud motor rotation of a drill bit of the drillstring.

[0151] As an example, where a tool that includes one or more magnetometers rotates, a circular pattern may be formed by values of Bx and By when plotted against each other. In such an example, in the absence of casing, the resulting plot may be close to a perfect circle. However, in the presence of casing, the resulting plot may form relatively random, incoherent patterns. As an example, a framework may provide for comparing an ideal circle (e.g., as a magnetometer performance feature) to input data (e.g., radial plane data) to thereby make a prediction as to casing status. For example, consider an approach that assesses how close plotted data are to an ideal case. In such an example, the closer the input data are to forming a perfect circle, the more likely it is that the tool is not within a cased portion of a borehole (e.g., past casing and into an open hole portion of a borehole). As an example, such a comparison may be performed by finding an ellipse-of-best-fit over a set of data and analyzing fit parameters.

[0152] FIG. 8 shows an example plot 800 of BT versus time during movement of a drillstring in a borehole with a cased portion and an uncased portion. As indicated, these data stabilize in a manner that corresponds to movement from the cased portion to the uncased portion (e.g., open hole portion) of the borehole. As an example, such data may be assessed as to a particular time, which may be associated with a particular distance (e.g., a measured depth, etc.), for example, to indicate an end of casing, which may be a casing shoe-end.

[0153] FIG. 9 shows example plots 910 and 920 of radial axes data, particularly Bx versus By, for a magnetometer where the plot 910 corresponds to a cased portion of a borehole and where the plot 920 corresponds to an uncased portion of a borehole. In the examples of FIG. 9, the data of each of the plots 910 and 920 may be data acquired with respect to a period of time, which may be a time window. As explained, data may be acquired while a tool that includes a magnetometer is rotating. Given such rotation, a plot of data of the individual axes (e.g., Bx and By) may be expected to form a circle, as shown in the plot 920; whereas, where interference exists due to metallic casing, these data may not form a circle, but rather, a distorted pattern that is not substantially circular as may be determined using equations for an ellipse and / or one or more other geometric constructs.

[0154] As an example, a framework may assess data with respect to one or more clusters. For example, consider an approach that may consider one or more dense clusters or density of a cluster or clusters. As an example, while steering a drillstring, sensors of a magnetometer may be temporarily concentrated in one direction, resulting in a Bx versus By plot looking like a cluster of points in one corner, which may affect performance of technique as these data may not form a complete circle (e.g., consider how rotation may provide for formation of a circle, etc.). As an example, a framework may discern one or more of such periods in time by assessing an Rx value. For example, one or more metrics, thresholds, etc., may be utilized to determine if a tool may be steering or not. For example, consider utilization of an equation such as LV<Rx<HV, where LV may be a low value and where HV may be a high value. In such an example, consider LV being approximately −1.5 and HV being approximately 1.5 where an Rx value within this range may indicate steering; whereas, if an Rx value is outside of this range, then that may indicate not steering. As an example, a framework may automatically indicate that these values correspond to an uncased portion of a borehole (e.g., an open hole portion). As an example, a framework may automatically set such values to a status as “uncased”.

[0155] As to the aforementioned Rx value, it may be determined using a particular gyroscope, which may be referred to as a “roll gyro”. Such a gyroscope may be an independent gyroscope that is included as a downhole instrument (e.g., as part of an MWD tool, etc.) to measure rotation speed of a drillstring and / or one or more components thereof. As an example, an Rx value may be a roll gyro measurement that may provide information as to whether a tool is trying to steer or is in a neutral position. As an example, an Rx value may be close to 0 when trying to steer and, for example, between approximately −2 and approximately −4 when neutral; noting that one or more types of references, scalings, transforms, etc., may be applied to a roll gyro measurement (e.g., Rx) to provide for suitable values that may be assessed using one or more techniques (e.g., thresholds, etc.).

[0156] FIG. 10 shows example plots 1010 and 1020 for data points that tend to be concentrated in a cluster when a drillstring is involved in steering. As shown in the plots 1010 and 1020, index numbers for Bx versus By are plotted where Rx may be assessed.

[0157] As an example, for data of frequency 5 Hz, a tool may receive 300 datapoints per minute. As an example, a framework may provide for setting a time period, a time interval, a time window, etc., based at least in part on an acquisition frequency. For example, consider an approach where a criterion may be given as a number of datapoints. In such an example, consider a criterion that calls for at least 100 datapoints, at least 200 datapoints, at least 300 datapoints, etc. In various example, trials, approximately 300 datapoints (e.g., plus or minus 15 percent) was deemed sufficient for robust and reliable performance. Where a frequency for data acquisition is 5 Hz, in a period of one minute, 300 datapoints may be acquired, which may be processed to make a real-time prediction (e.g., a prediction as to cased or uncased at an interval of approximately one minute). As an example, a framework may provide for implementing a technique where sensor readings values are forward-filled to take care of missing values.

[0158] As explained, a framework may utilize a number of techniques, which may include a rate-of-change (ROC) of BT value technique, an eccentricity of ellipse-of-best-fit (EBF) technique, a degree of spread of raw data from a fitted ellipse (SFE) technique, an ideal BT and diameter of an ellipse (IBT) technique, etc.

[0159] As to the ROC technique, as observed in FIG. 8, values during cased regions jump around erratically but seem sensible for the remainder of a downhole run. In such an example, a framework may infer that the rate-of-change (ROC) of the BT value will be extremely steep when compared to the general trajectory of the uncased region. As an example, an average value of a 300-datapoint window may be computed. Next, the ROC between this average and the average of the next 300 datapoints (e.g., with no step value in between) may be computed. In such an example, if the mode of the percent change of the ROC is above a threshold of 0.0003, the datapoints in that window may be classified as “cased”.

[0160] As to an EBF technique, as explained, eccentricity of an ellipse may be a suitable measure of how circular data are when plotted. For example, a perfect circle has eccentricity of 0. In such an approach, if an ellipse-of-best-fit computed on a 300-datapoint window is close to 0 (e.g., within some tolerance threshold), the data points in that window may be classified as “uncased”.

[0161] As to a SFE technique, which may consider degree of spread of raw data from a fitted ellipse, consider an altered version of an equation of an ellipse, where the equation is given below followed by the altered version:x2a2+y2b2=1B⁢x2b2+B⁢y2a2=1where a and b represent the semi-minor and semi-major axes respectively.In this example SFE technique, when substituting the values of Bx and By with the sensor readings, if the result is equal to 1, it insinuates that the raw data are more or less on the fitted ellipse. If the equation result is approximately equal to 1 for a 300-datapoint window, all datapoints in that window may be classified as “uncased”.

[0163] As to an IBT technique, which may consider an ideal BT and diameter of an ellipse, as an example, a theoretical ideal BT value may be computed for a certain point in a run, for example, using the following formula:BT=B⁢(1-(cos⁢ I)⁢(sin⁢ D)+(cos⁢ A)⁢(cos⁢ D)⁢(sin⁢ I)2where B=predicted value of Earth's magnetic field in that region, I=inclination, D=magnetic dip angle, and A=azimuth.In the foregoing equation, as azimuth values tend to be contaminated from faulty magnetometer readings, such an equation may be adapted to a lower and upper bound, for example, by assuming the values of cosA to be at least −1 and at most 1:BT=B⁢(1-(cos⁢ I)⁢(sin⁢ D)+(cos⁢ D)⁢(sin⁢ I)2BT=B⁢(1-(cos⁢ I)⁢(sin⁢ D)-(cos⁢ D)⁢(sin⁢ I)2As an example, a framework may provide for computed a BT value as BT=√{square root over (Bx2+By2)}. In such an example, if the average of the recorded BT values of a 300-datapoint window is either within the range of the two predicted BT values or approximately equal to either one of them, datapoints in that window are classified as “uncased”.

[0166] As an example, a framework may provide for making a final prediction that may rely on a number of predictions. For example, a final prediction may be based on a combination of results of two or more of the aforementioned techniques. As an example, a datapoint or datapoints may be classified as “cased” if a majority vote is determined from a number of individual techniques. As an example, if there is a tie, a framework may automatically classify as an “uncased” scenario. As an example, a framework may provide for quantifying uncertainty of one or more predictions, for example, by counting the number of techniques that voted “cased”.

[0167] As an example, a framework may provide for making rapid determinations using a number of different techniques where the framework may provide for generating a number of classifications using two or more combinations of different techniques. For example, consider an approach where four techniques are applicable for a framework where combinations can include two techniques, three techniques, and four techniques. In such an approach, ten different combinations may be possible where uncertainties may be generated for each of the different combinations. As to two techniques, 50 percent or 100 percent may result; as to three techniques, 33 percent, 66 percent, or 100 percent may result; as to four techniques, 25 percent, 50 percent, 75 percent, or 100 percent may result. As an example, upon acquisition of sufficient data, a framework may resort to weighting outcomes from individual techniques. As an example, a framework may provide for selecting a particular combination of techniques based on performance.

[0168] As an example, a method may include determining whether a magnetometer is in proximity of magnetic interference in a borehole. In such an example, the method may employ a number of techniques, which may be selected from a group of techniques. As an example, a method may involve tracking the rate-of-change of BT over a short window of time; and comparing a plot of Bx versus By to ideal conditions of one or more of (i) eccentricity, (ii) semi-major and semi-minor axes, (iii) diameter, and (iv) degree of spread of datapoints from a fitted ellipse.

[0169] As an example, a method may provide for using one or more techniques independently and / or within one or more permutations of a group of such techniques.

[0170] As an example, a method may include implementing a criterion as to number of datapoints to be considered to form a dataset, which may be within a time window. For example, consider a 300 datapoint long window. As an example, a method may include adjusting a criterion, which may be adjusted based on one or more conditions, which may depend on certainty, uncertainty, speed of a tool being moved in a borehole, rotation rate of a drillstring, etc. As an example, a 300-datapoints long window may be increased and / or decreased to a desired length as per one or more domain requirements and / or tool configuration.

[0171] As an example, a framework may provide for implementing one or more machine learning models. As to types of machine learning models, consider, for example, one or more of a support vector machine (SVM) model, a k-nearest neighbors (KNN) model, an ensemble classifier model, a neural network (NN) model, etc. As an example, a machine learning model may be a deep learning model (e.g., deep Boltzmann machine, deep belief network, convolutional neural network, stacked auto-encoder, etc.), an ensemble model (e.g., random forest, gradient boosting machine, bootstrapped aggregation, AdaBoost, stacked generalization, gradient boosted regression tree, etc.), a neural network model (e.g., radial basis function network, perceptron, back-propagation, Hopfield network, etc.), a regularization model (e.g., ridge regression, least absolute shrinkage and selection operator, elastic net, least angle regression), a rule system model (e.g., cubist, one rule, zero rule, repeated incremental pruning to produce error reduction), a regression model (e.g., linear regression, ordinary least squares regression, stepwise regression, multivariate adaptive regression splines, locally estimated scatterplot smoothing, logistic regression, etc.), a Bayesian model (e.g., naïve Bayes, average on-dependence estimators, Bayesian belief network, Gaussian naïve Bayes, multinomial naïve Bayes, Bayesian network), a decision tree model (e.g., classification and regression tree, iterative dichotomiser 3, C4.5, C5.0, chi-squared automatic interaction detection, decision stump, conditional decision tree, M5), a dimensionality reduction model (e.g., principal component analysis, partial least squares regression, Sammon mapping, multidimensional scaling, projection pursuit, principal component regression, partial least squares discriminant analysis, mixture discriminant analysis, quadratic discriminant analysis, regularized discriminant analysis, flexible discriminant analysis, linear discriminant analysis, etc.), an instance model (e.g., k-nearest neighbor, learning vector quantization, self-organizing map, locally weighted learning, etc.), a clustering model (e.g., k-means, k-medians, expectation maximization, hierarchical clustering, etc.), etc.

[0172] As an example, a machine model, which may be a machine learning model (ML model), may be built using a computational framework with a library, a toolbox, etc., such as, for example, those of the MATLAB framework (MathWorks, Inc., Natick, Massachusetts). The MATLAB framework includes a toolbox that provides supervised and unsupervised machine learning algorithms, including support vector machines (SVMs), boosted and bagged decision trees, k-nearest neighbor (KNN), k-means, k-medoids, hierarchical clustering, Gaussian mixture models, and hidden Markov models. Another MATLAB framework toolbox is the Deep Learning Toolbox (DLT), which provides a framework for designing and implementing deep neural networks with algorithms, pretrained models, and apps. The DLT provides convolutional neural networks (ConvNets, CNNs) and long short-term memory (LSTM) networks to perform classification and regression on image, time-series, and text data. The DLT includes features to build network architectures such as generative adversarial networks (GANs) and Siamese networks using custom training loops, shared weights, and automatic differentiation. The DLT provides for model exchange various other frameworks.

[0173] As an example, the TENSORFLOW framework (Google LLC, Mountain View, CA) may be implemented, which is an open-source software library for dataflow programming that includes a symbolic math library, which may be implemented for machine learning applications that may include neural networks. As an example, the CAFFE framework may be implemented, which is a DL framework developed by Berkeley Al Research (BAIR) (University of California, Berkeley, California). As another example, consider the SCIKIT platform (e.g., scikit-learn), which utilizes the PYTHON programming language. As an example, a framework such as the APOLLO Al framework may be utilized (APOLLO.AI GmbH, Germany). As an example, a framework such as the PYTORCH framework may be utilized (Facebook Al Research Lab (FAIR), Facebook, Inc., Menlo Park, California).

[0174] As an example, a training method may include various actions that may operate on a dataset to train an ML model. As an example, a dataset may be split into training data and test data where test data may provide for evaluation. A method may include cross-validation of parameters and best parameters, which may be provided for model training.

[0175] The TENSORFLOW framework may run on multiple CPUs and GPUS (with optional CUDA (NVIDIA Corp., Santa Clara, California) and SYCL (The Khronos Group Inc., Beaverton, Oregon) extensions for general-purpose computing on graphics processing units (GPUS)). TENSORFLOW is available on 64-bit LINUX, MACOS (Apple Inc., Cupertino, California), WINDOWS (Microsoft Corp., Redmond, Washington), and mobile computing platforms including ANDROID (Google LLC, Mountain View, California) and IOS (Apple Inc.) operating system-based platforms.

[0176] TENSORFLOW computations may be expressed as stateful dataflow graphs; noting that the name TENSORFLOW derives from the operations that such neural networks perform on multidimensional data arrays. Such arrays may be referred to as “tensors”.

[0177] As an example, a device may utilize TENSORFLOW LITE (TFL) or another type of lightweight framework. For example, consider a gateway that may be in the field (e.g., on-site) and that may utilize the TFL and / or one or more other types of lightweight frameworks. The TFL framework is a set of tools that enables on-device machine learning where models may run on mobile, embedded, and IoT devices. The TFL framework is optimized for on-device machine learning, by addressing latency (no round-trip to a server), privacy (no personal data leaves the device), connectivity (Internet connectivity is demanded), size (reduced model and binary size) and power consumption (e.g., efficient inference and a lack of network connections). The TFL framework offers multiple platform support, covering ANDROID and iOS devices, embedded LINUX, and microcontrollers. The TFL framework offers diverse language support includes JAVA, SWIFT, Objective-C, C++, and PYTHON. The TFL framework may provide high performance via hardware acceleration and model optimization.

[0178] FIG. 11 shows an example of a method 1100 that includes an acquisition block 1110 for acquiring magnetometer data using a downhole tool of a drillstring in a borehole, where the borehole includes at least one transition point between a cased portion of the borehole and an uncased portion of the borehole; a selection block 1120 for selecting a number of techniques from a group of techniques implementable using downhole circuitry of the drillstring; an application block 1130 for applying the number of techniques to one or more portions of the magnetometer data to generate a corresponding number of results, where each of the results is indicative of a position of the downhole tool being within the cased portion or the uncased portion; and a control block 1140 for, based on at least two of the results, controlling movement of the drillstring in the borehole. For example, consider controlling the drillstring to drill further into the subsurface environment to lengthen the borehole.

[0179] The method 1100 of FIG. 11 is shown as including various computer-readable storage medium (CRM) blocks 1111, 1121, 1131, and 1141 that may include processor-executable instructions that may instruct a computing system, which may be a control system, to perform one or more of the actions described with respect to the method 1100.

[0180] As shown in the example of FIG. 11, the system 1190 may include one or more computers 1192 that include one or more processors 1193, memory 1194 operatively coupled to at least one of the one or more processors 1193, instructions 1196 that may be, for example, stored in the memory 1194, and one or more interfaces 1195 (e.g., one or more network interfaces and / or other interfaces). As an example, the system 1190 may include one or more processor-readable media that include processor-executable instructions executable by at least one of the one or more processors 1193 to cause the system 1190 to perform actions such as, for example, one or more actions of the method 1100. As an example, the instructions 1196 may include instructions of one or more of the CRM blocks 1111, 1121, 1131, and 1141. The memory 1194 may be or include the one or more processor-readable media where the processor-executable instructions may be or include instructions. As an example, a processor-readable medium may be a computer-readable storage medium that is non-transitory that is not a signal and that is not a carrier wave.

[0181] As an example, the system 1190 may include subsystems. For example, the system 1190 may include a plurality of subsystems that may operate using equipment that is distributed where a subsystem may be referred to as being a system. For example, consider a downhole tool system and a surface system. As an example, operations of the blocks 1110, 1120, and 1130 of the method 1100 may be performed using a downhole tool system. As an example, operations of the block 1140 of the method 1100 may be performed using a downhole tool system (e.g., consider in integrated controller in a drillstring). The method 1100 may be implemented using, for example, a downhole system and / or a surface system, which may be a cloud-based or cloud-coupled system.

[0182] As an example, a method may include acquiring magnetometer data using a downhole tool of a drillstring in a borehole, where the borehole includes at least one transition point between a cased portion of the borehole and an uncased portion of the borehole; selecting a number of techniques from a group of techniques implementable using downhole circuitry of the drillstring; applying the number of techniques to one or more portions of the magnetometer data to generate a corresponding number of results, where each of the results is indicative of a position of the downhole tool being within the cased portion or the uncased portion; and, based on at least two of the results, controlling movement of the drillstring in the borehole. In such an example, the magnetometer data can include magnetometer data acquired during rotation of the downhole tool in the borehole.

[0183] As an example, magnetometer data can include magnetometer data acquired when the downhole tool is not being rotated in the borehole. In such an example, one of a number of techniques may determine that at least a portion of the magnetometer data were acquired when the downhole tool was in the uncased portion of the borehole, at least in part during execution of a steering operation of the drillstring. In such an example, the one of the number of techniques may include a cluster analysis technique.

[0184] As an example, a number of techniques may include one or more of a rate-of-change technique and an eccentricity technique. In such an example, an eccentricity technique may include determining eccentricity of two magnetic vector components of the magnetometer data with respect to an equation for an ellipse.

[0185] As an example, a number of techniques may include a degree of spread from a fitted geometric structure technique. For example, consider a fitted geometric structure technique that may utilize an equation for an ellipse.

[0186] As an example, a number of techniques may include a technique that computes an ideal BT value and compares an actual BT value to the ideal BT value.

[0187] As an example, a method may include determining one of the at least one transition point.

[0188] As an example, a method may include performing the method in real-time (e.g., with a drillstring in a borehole).

[0189] As an example, magnetometer data can include a number of datapoints according to a datapoint threshold. For example, consider a datapoint threshold that is approximately 300 datapoints.

[0190] As an example, magnetometer data may be acquired during rotation of a drillstring in a borehole and translation of the drillstring in the borehole. In such an example, a drillstring may be translated in a borehole at a tripping rate, for example, where the tripping rate depends on connection times for making connections between stands of drillpipe that form the drillstring. As an example, a drillstring may be translated in a borehole at a rate of penetration, for example, where the rate of penetration depends on breaking rock at an end of the borehole to lengthen the borehole.

[0191] As an example, a method may include filtering magnetometer data based at least in part on results.

[0192] As an example, a method may include combining results according to two or more permutations of a number of techniques.

[0193] As an example, a method may include determining an uncertainty of a combination of results for two or more techniques.

[0194] As an example, a method may include controlling movement of a drillstring in a borehole that includes steering the drillstring for directional drilling that lengthens the borehole.

[0195] As an example, controlling movement of a drillstring in a borehole may include controlling the drillstring with respect to mud dynamics. In such an example, the mud dynamics correspond to swab or surge. As an example, swab and / or surge may depend on where a drillstring is with respect to a cased portion or an uncased portion of a borehole. For example, dynamics of mud and drillstring interactions may differ when a drillstring is entirely or predominantly within a cased portion when compared to the drillstring being more so in an uncased portion.

[0196] As an example, controlling movement of a drillstring in a borehole may include controlling the movement with respect to identification of one of at least one transition point (e.g., a transition point between cased and uncased portions of a borehole).

[0197] As an example, a system can include a processor; memory accessible to the processor; and processor-executable instructions stored in the memory and executable by the processor to instruct the system to: acquire magnetometer data using a downhole tool of a drillstring in a borehole, where the borehole includes at least one transition point between a cased portion of the borehole and an uncased portion of the borehole; select a number of techniques from a group of techniques implementable using downhole circuitry of the drillstring; apply the number of techniques to one or more portions of the magnetometer data to generate a corresponding number of results, where each of the results is indicative of a position of the downhole tool being within the cased portion or the uncased portion; and, based on at least two of the results, control movement of the drillstring in the borehole.

[0198] As an example, one or more non-transitory computer-readable storage media may include processor-executable instructions executable to instruct a processor to: acquire magnetometer data using a downhole tool of a drillstring in a borehole, where the borehole includes at least one transition point between a cased portion of the borehole and an uncased portion of the borehole; select a number of techniques from a group of techniques implementable using downhole circuitry of the drillstring; apply the number of techniques to one or more portions of the magnetometer data to generate a corresponding number of results, where each of the results is indicative of a position of the downhole tool being within the cased portion or the uncased portion; and, based on at least two of the results, control movement of the drillstring in the borehole.

[0199] As an example, one or more computer-readable storage media may include processor-executable instructions to instruct a computing system to perform one or more methods. In such an example, the one or more computer-readable storage media may be a program product (e.g., a computer program product, a computer system program product, etc.).

[0200] In some embodiments, a method or methods may be executed by a computing system. FIG. 12 shows an example of a system 1200 that may include one or more computing systems 1201-1, 1201-2, 1201-3 and 1201-4, which may be operatively coupled via one or more networks 1209, which may include wired and / or wireless networks.

[0201] As an example, a system may include an individual computer system or an arrangement of distributed computer systems. In the example of FIG. 12, the computer system 1201-1 may include one or more sets of instructions 1202, which may be or include processor-executable instructions, for example, executable to perform various tasks (e.g., receiving information, requesting information, processing information, simulation, outputting information, etc.).

[0202] As an example, a set of instructions may be executed independently, or in coordination with, one or more processors 1204, which is (or are) operatively coupled to one or more storage media 1206 (e.g., via wire, wirelessly, etc.). As an example, one or more of the one or more processors 1204 may be operatively coupled to at least one of one or more network interface 1207. In such an example, the computer system 1201-1 may transmit and / or receive information, for example, via the one or more networks 1209 (e.g., consider one or more of the Internet, a private network, a cellular network, a satellite network, etc.). As shown, one or more other components 1208 may be included.

[0203] As an example, the computer system 1201-1 may receive from and / or transmit information to one or more other devices, which may be or include, for example, one or more of the computer systems 1201-2, etc. A device may be located in a physical location that differs from that of the computer system 1201-1. As an example, a location may be, for example, a processing facility location, a data center location (e.g., server farm, etc.), a rig location, a wellsite location, a downhole location, etc.

[0204] As an example, a processor may be or include a microprocessor, microcontroller, processor component or subsystem, programmable integrated circuit, programmable gate array, or another control or computing device.

[0205] As an example, the storage media 1206 may be implemented as one or more computer-readable or machine-readable storage media. As an example, storage may be distributed within and / or across multiple internal and / or external enclosures of a computing system and / or additional computing systems.

[0206] As an example, a storage medium or storage media may include one or more different forms of memory including semiconductor memory devices such as dynamic or static random access memories (DRAMs or SRAMs), erasable and programmable read-only memories (EPROMs), electrically erasable and programmable read-only memories (EEPROMs) and flash memories, magnetic disks such as fixed, floppy and removable disks, other magnetic media including tape, optical media such as compact disks (CDs) or digital video disks (DVDs), BLUERAY disks, or other types of optical storage, or other types of storage devices.

[0207] As an example, a storage medium or media may be located in a machine running machine-readable instructions, or located at a remote site from which machine-readable instructions may be downloaded over a network for execution.

[0208] As an example, various components of a system such as, for example, a computer system, may be implemented in hardware, software, or a combination of both hardware and software (e.g., including firmware), including one or more signal processing and / or application specific integrated circuits.

[0209] As an example, a system may include a processing apparatus that may be or include a general-purpose processors or application specific chips (e.g., or chipsets), such as ASICs, FPGAs, PLDs, or other appropriate devices.

[0210] As an example, a device may be a mobile device that includes one or more network interfaces for communication of information. For example, a mobile device may include a wireless network interface (e.g., operable via IEEE 802.11, ETSI GSM, BLUETOOTH, satellite, etc.). As an example, a mobile device may include components such as a main processor, memory, a display, display graphics circuitry (e.g., optionally including touch and gesture circuitry), a SIM slot, audio / video circuitry, motion processing circuitry (e.g., accelerometer, gyroscope), wireless LAN circuitry, smart card circuitry, transmitter circuitry, GPS circuitry, and a battery. As an example, a mobile device may be configured as a cell phone, a tablet, etc. As an example, a method may be implemented (e.g., wholly or in part) using a mobile device. As an example, a system may include one or more mobile devices.

[0211] As an example, a system may be a distributed environment, for example, a so-called “cloud” environment where various devices, components, etc. interact for purposes of data storage, communications, computing, etc. As an example, a device or a system may include one or more components for communication of information via one or more of the Internet (e.g., where communication occurs via one or more Internet protocols), a cellular network, a satellite network, etc. As an example, a method may be implemented in a distributed environment (e.g., wholly or in part as a cloud-based service).

[0212] As an example, information may be input from a display (e.g., consider a touchscreen), output to a display or both. As an example, information may be output to a projector, a laser device, a printer, etc. such that the information may be viewed. As an example, information may be output stereographically or holographically. As to a printer, consider a 2D or a 3D printer. As an example, a 3D printer may include one or more substances that may be output to construct a 3D object. For example, data may be provided to a 3D printer to construct a 3D representation of a subterranean formation. As an example, layers may be constructed in 3D (e.g., horizons, etc.), geobodies constructed in 3D, etc. As an example, holes, fractures, etc., may be constructed in 3D (e.g., as positive structures, as negative structures, etc.).

[0213] Although only a few examples have been described in detail above, those skilled in the art will readily appreciate that many modifications are possible in the examples. Accordingly, all such modifications are intended to be included within the scope of this disclosure as defined in the following claims. In the claims, means-plus-function clauses are intended to cover the structures described herein as performing the recited function and not only structural equivalents, but also equivalent structures. Thus, although a nail and a screw may not be structural equivalents in that a nail employs a cylindrical surface to secure wooden parts together, whereas a screw employs a helical surface, in the environment of fastening wooden parts, a nail and a screw may be equivalent structures.

Examples

Embodiment Construction

[0018]The following description includes embodiments of the best mode presently contemplated for practicing the described implementations. This description is not to be taken in a limiting sense, but rather is made merely for the purpose of describing the general principles of the implementations. The scope of the described implementations should be ascertained with reference to the issued claims.

[0019]A borehole may be referred to as a wellbore and may include an openhole portion or an uncased portion and / or may include a cased portion. As explained, a borehole may include a transition point between a cased portion and an uncased portion. In various instances, a borehole may include one or more cased portions and one or more uncased portions. As an example, a borehole may be defined by a bore wall that is composed of rock that bounds the borehole, noting that casing may be disposed in a borehole where the casing may act as a fluid barrier and / or as a stabilizer. As an example, a po...

Claims

1. A method comprising:acquiring magnetometer data using a downhole tool of a drillstring in a borehole, wherein the borehole comprises at least one transition point between a cased portion of the borehole and an uncased portion of the borehole;selecting a number of techniques from a group of techniques implementable using downhole circuitry of the drillstring;applying the number of techniques to one or more portions of the magnetometer data to generate a corresponding number of results, wherein each of the results is indicative of a position of the downhole tool being within the cased portion or the uncased portion; andbased on at least two of the results, controlling movement of the drillstring in the borehole.

2. The method of claim 1, wherein the magnetometer data comprise magnetometer data acquired during rotation of the downhole tool in the borehole.

3. The method of claim 1, wherein the magnetometer data comprise magnetometer data acquired when the downhole tool is not being rotated in the borehole.

4. The method of claim 3, wherein one of the number of techniques determines that at least a portion of the magnetometer data were acquired when the downhole tool was in the uncased portion of the borehole, at least in part during execution of a steering operation of the drillstring.

5. The method of claim 4, wherein the one of the number of techniques comprises a cluster analysis technique.

6. The method of claim 1, wherein the number of techniques comprise a rate-of-change technique.

7. The method of claim 1, wherein the number of techniques comprise an eccentricity technique.

8. The method of claim 7, wherein the eccentricity technique comprises determining eccentricity of two magnetic vector components of the magnetometer data with respect to an equation for an ellipse.

9. The method of claim 1, wherein the number of techniques comprise a degree of spread from a fitted geometric structure technique.

10. The method of claim 9, wherein the fitted geometric structure technique utilizes an equation for an ellipse.

11. The method of claim 1, wherein the number of techniques comprise a technique that computes an ideal BT value and compares an actual BT value to the ideal BT value.

12. The method of claim 1, comprising determining one of the at least one transition point.

13. The method of claim 1, comprising performing the method in real-time.

14. The method of claim 1, wherein the magnetometer data comprise a number of datapoints according to a datapoint threshold.

15. The method of claim 14, wherein the datapoint threshold is approximately 300 datapoints.

16. The method of claim 1, wherein the magnetometer data are acquired during rotation of the drillstring in the borehole and translation of the drillstring in the borehole.

17. The method of claim 16, wherein the drillstring is translated in the borehole at a tripping rate, and wherein the tripping rate depends on connection times for making connections between stands of drillpipe that form the drillstring.

18. The method of claim 16, wherein the drillstring is translated in the borehole at a rate of penetration, and wherein the rate of penetration depends on breaking rock at an end of the borehole to lengthen the borehole.

19. The method of claim 1, comprising filtering the magnetometer data based at least in part on the results.

20. The method of claim 1, comprising combining the results according to two or more permutations of the number of techniques.

21. The method of claim 1, comprising determining an uncertainty of a combination of the results for two or more of the techniques.

22. The method of claim 1, wherein the controlling movement of the drillstring in the borehole comprises steering the drillstring for directional drilling that lengthens the borehole.

23. The method of claim 1, wherein the controlling movement of the drillstring in the borehole comprises controlling the drillstring with respect to mud dynamics.

24. The method of claim 23, wherein the mud dynamics correspond to swab or surge.

25. The method of claim 1, wherein the controlling movement of the drillstring in the borehole comprises controlling the movement with respect to identification of one of the at least one transition point.

26. A system comprising:a processor;memory accessible to the processor; andprocessor-executable instructions stored in the memory and executable by the processor to instruct the system to:acquire magnetometer data using a downhole tool of a drillstring in a borehole, wherein the borehole comprises at least one transition point between a cased portion of the borehole and an uncased portion of the borehole;select a number of techniques from a group of techniques implementable using downhole circuitry of the drillstring;apply the number of techniques to one or more portions of the magnetometer data to generate a corresponding number of results, wherein each of the results is indicative of a position of the downhole tool being within the cased portion or the uncased portion; andbased on at least two of the results, control movement of the drillstring in the borehole.

27. One or more non-transitory computer-readable storage media comprising processor-executable instructions executable to instruct a processor to:acquire magnetometer data using a downhole tool of a drillstring in a borehole, wherein the borehole comprises at least one transition point between a cased portion of the borehole and an uncased portion of the borehole;select a number of techniques from a group of techniques implementable using downhole circuitry of the drillstring;apply the number of techniques to one or more portions of the magnetometer data to generate a corresponding number of results, wherein each of the results is indicative of a position of the downhole tool being within the cased portion or the uncased portion; andbased on at least two of the results, control movement of the drillstring in the borehole.

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