Marker assembly including sacrificial barrier component

Abstract

An apparatus for determining a position of an inner string within an outer string includes an axis parallel to a longitudinal axis of the inner string and a marker assembly disposed at a marker location in the outer string, the outer string configured to be deployed into a borehole in a subterranean region, the inner string configured to be advanced through the outer string. The marker assembly includes a blocking component configured to impede axial movement of the inner string through the outer string at the marker location, the blocking component configured to be displaced in response to an axial force applied to the blocking component by the inner string to permit axial advancement of the inner string beyond the marker assembly.

Description

[0001] Cross-reference to related applications

[0002] This application claims the benefit of U.S. Application Serial No. 63 / 045,425, filed on June 29, 2020, the entire disclosure of which is incorporated herein by reference. Background Technology

[0003] In the resource extraction industry, various operations are performed to assess resource-bearing formations and recover resources such as hydrocarbons. These operations include drilling, directional drilling, completion, and production operations. The drilling and completion process typically involves deploying a drill string with a drill bit, drilling a section of borehole, removing the drill string, and subsequently deploying a section of casing or tailpipe and cementing the casing or tailpipe into the borehole.

[0004] In addition to conventional drilling, techniques have been developed in which a liner, casing, or other tubing is advanced using drilling assemblies during the drilling process. These techniques include casing drilling and liner drilling. In casing drilling, a bottom drill string assembly, including the drill bit, is attached to a section of casing, and after drilling, the casing hangs at the top of the wellbore. In liner drilling, a cemented liner serves as part of the drill string, advances in the borehole, and / or rotates within the borehole with the drill string, and remains in place after the drill string is removed from the borehole. The liner may rotate with the drill string, or a mud motor may be attached to the drill string and used to rotate the drill bit when the liner is not rotating. Summary of the Invention

[0005] An embodiment of an apparatus for determining the position of an inner tubing string within an outer tubing string includes: an axis parallel to the longitudinal axis of the inner tubing string; and a marking assembly disposed at a marking location within the outer tubing string, the outer tubing string being configured to be deployed into a borehole in an underground area, the inner tubing string being configured to advance through the outer tubing string. The marking assembly includes a blocking member configured to impede axial movement of the inner tubing string through the outer tubing string at the marking location, the blocking member being configured to displace in response to an axial force applied to the blocking member by the inner tubing string to allow axial advancement of the inner tubing string beyond the marking assembly.

[0006] An embodiment of a method for determining the position of an inner tubing string in a downhole system includes: deploying an outer tubing string into a borehole in a subsurface area, the outer tubing string including a marking assembly comprising a blocking member disposed at a marked location within the outer tubing string; and deploying and advancing the inner tubing string until it engages the blocking member, the blocking member impeding axial movement of the inner tubing string at the marked location. The method further includes: performing measurements to determine the position of the inner tubing string relative to the outer tubing string; displacing the blocking member by applying an axial force from the inner tubing string to the blocking member to allow axial advancement of the inner tubing string beyond the marking assembly; and performing downhole operations based on the measurements. Attached Figure Description

[0007] The following description should not be considered as limiting in any way. Referring to the accompanying drawings, the same elements are indicated by the same reference numerals:

[0008] Figure 1 The implementation scheme for the drilling and / or completion system is described;

[0009] Figure 2 An embodiment of a marking assembly disposed in the outer tubing of a tailpipe drilling system is described, the marking assembly including a sacrificial blocking component;

[0010] Figure 3 Depicting Figure 2 An implementation scheme for the force distribution component of the marking assembly;

[0011] Figure 4 Depicting Figure 2 and Figure 3 An embodiment of the marking component includes elements made of a different material than the sacrificial blocking component and the force distribution component;

[0012] Figure 5 It is a flowchart depicting the process of assembling drilling and completion systems and drilling a section or length of borehole;

[0013] Figure 6 An embodiment of an outer tubing string for a drilling and completion assembly deployed in a borehole is described, the drilling and completion assembly including a marker assembly with a sacrificial blocking component;

[0014] Figure 7 The image depicts the assembly phase during which the drill bit engages the inner tubing with the stop component. Figure 6 Drilling and completion components;

[0015] Figure 8 Depicts the assembly phase in which sufficient force is applied by the drill bit to the stopping component to crush, break, or otherwise pulverize it. Figure 6 and Figure 7 Drilling and completion components; and

[0016] Figure 9 The description depicts the assembly phase during which the drilling assembly, including the drill bit, is axially advanced beyond the marking assembly to drill the borehole length. Figures 6 to 8 Drilling and completion components. Detailed Implementation

[0017] Detailed descriptions of one or more embodiments of the devices and methods disclosed herein are presented by way of example rather than limitation, with reference to the accompanying drawings.

[0018] Systems, apparatus, and methods are provided for determining the relative position of the inner tubing string within the outer tubing string of a drilling system. Implementations of the drilling and completion system include a marking assembly positioned at a fixed location within the outer tubing string. The outer tubing string may include a liner, casing, or other fittings left in the borehole after drilling. The inner tubing string includes a drilling assembly and a drill bit configured to advance through the outer tubing string. After the drilling assembly has advanced beyond the outer tubing string, the drilling assembly is operated to drill a section of borehole. The outer tubing string is advanced with the drilling assembly during drilling and may be cemented in place after the section is drilled.

[0019] Implementations of the marking assembly include a sacrificial blocking member at a fixed location within the outer tubing string. The blocking member extends radially inward into the conduit formed by the outer tubing string and is configured to impede axial movement of the inner tubing string through the outer tubing string and through the conduit when the drill bit contacts or otherwise engages the blocking member. In one embodiment, "axial" movement refers to movement along the longitudinal axis of the inner and / or outer tubing strings in the downhole direction (e.g., Figure 2 The movement of axis A) is shown. The blocking component allows measurement of the position of the inner tubing relative to the outer tubing to ensure proper positioning of the inner tubing within the outer tubing. After measurement, the drilling pressure is increased to apply an axial force sufficient to crush the blocking component. The inner tubing can then be advanced in the downhole direction past the marker assembly to reach the drilling position, secured to the outer tubing, and the system can be operated to drill the borehole length. The measurement of the position of the inner tubing relative to the outer tubing can be considered as the calibration of the inner tubing's position within the outer tubing.

[0020] In one implementation, the marking assembly and / or sacrificial blocking component is positioned at or near the lowest point of the outer tubing or downhole end (e.g., at or as close as possible to the lowest point). For example, as discussed further below, the blocking component may be located at the liner shoe or other fitting. Positioning the blocking component in this way can be beneficial for compensating for tolerances in length dimensions, different deformations of the inner and outer tubing (e.g., different stretching of the outer and inner tubing due to gravity), and potential errors in the recorded or measured length dimensions of the outer and inner tubing. Note that a “lower” component or location is a component or location further from the ground than a reference location and corresponds to the lower true vertical depth (TVD) or lower measured depth (MD). A “downhole” location is a location further from the ground than a reference location. Movement in the downhole direction refers to axial movement along the borehole or along the outer tubing away from the ground. Therefore, movement in the surface direction refers to axial movement along the borehole or along the outer tubing toward the ground.

[0021] The blocking member is configured to displace in response to an axial force to release the obstruction and allow the inner tubing to move in the downhole direction past the location of the marking assembly. The inner tubing can then be advanced to the desired location in the borehole to prepare for drilling and completion assemblies. In one embodiment, the blocking member is made of a material and / or configured to break into fragments that can be circulated out of the borehole or otherwise crushed small enough not to interfere with the functionality of the drilling and completion processes. In another embodiment, the blocking member may be made of a resilient, flexible, and / or deformable material that is deformable and propelled through the outer tubing. It should be noted that in some embodiments, the marking assembly and / or blocking member comprises various combinations of materials.

[0022] In one embodiment, the blocking member is made of a material having material properties selected such that axial forces applied by the inner tubing (with or without rotating the drill bit) cause the blocking member to break or pulverize into small fragments that can be circulated out of the borehole or will not pose a risk to subsequent drilling operations. For example, the blocking member is made of glass and / or other brittle materials selected such that axial forces above a threshold cause the blocking member to break, crush, or otherwise pulverize into fragments small enough to circulate with the borehole fluid. The fragments or pieces of the blocking member can be of various sizes and can be ground into even smaller fragments during subsequent drilling operations without damaging the drill bit until they are small enough to circulate with the borehole fluid. In another embodiment, the blocking member is perforated or otherwise formed such that it breaks into fragments of a desired size or size range.

[0023] In one embodiment, the blocking component may be made of a material that can be sheared during the application of an axial force exerted by the inner tubing (e.g., by a drill bit), and subsequently broken, fragmented, crushed, or ground at a later time to reduce the material to a size small enough to be circulated to the ground with the borehole fluid, where the material is filtered out from the borehole fluid. For example, the material and / or size of the fragments are selected such that the material can be ground when the drill bit rotation is established in a later state.

[0024] The embodiments described herein offer numerous advantages. For example, the blocking component provides a simple and effective way to mark the inner tubing string and measure its position relative to the outer tubing string without requiring potentially more complex components, such as sensors or other marking mechanisms. Conventional liner drilling systems, for instance, utilize sensors that require data transmission and analysis, or landing splines that could potentially break and become stuck in the borehole. The described embodiments provide an efficient marking method that eliminates the need for sensors or components that could potentially remain in the wellbore and interfere with drilling operations (e.g., splines, radial bolts, etc.).

[0025] Figure 1 An example of a system 10 is shown that can be used to perform one or more underground operations such as drilling and well completion. System 10 includes a downhole component 12 disposed in a borehole 14 penetrating at least one formation 16. While the borehole 14 is in Figure 1 The borehole is shown as having a constant diameter, but those skilled in the art will understand that the borehole is not limited thereto. For example, the borehole 14 may have a varying diameter and / or orientation (e.g., azimuth and inclination). The downhole component 12 includes various parts or assemblies, such as drilling assemblies and various measuring tools and communication assemblies, one or more of which may be configured as a bottom hole assembly (BHA).

[0026] In one embodiment, system 10 includes a drilling and completion assembly 20 having a drill bit 22 or other shredding device. The drill bit 22 can be driven by rotating an inner tubing string 30 and / or using a downhole motor (e.g., a mud motor). System 10 has surface equipment 24, which includes various components for performing tasks such as deploying downhole components, adding drill pipe or other tubing string components, rotating the borehole string, acquiring measurements, etc. The surface equipment may include a derrick, top drive unit, hook, rotary table, and winch.

[0027] System 10 also includes components for facilitating the circulation of fluids (such as drilling mud and / or cement slurry) through the inner bore of the inner tubing 30 and the annulus between the inner tubing 30 and the borehole 14 or the outer tubing 32. A pumping unit 26 is located at the surface to circulate fluid from a mud pit or other fluid source 28 through a riser, into the inner bore of the inner tubing 30, and into the borehole 14.

[0028] In one embodiment, system 10 includes the capability to perform drilling operations in which completion components or other fittings are deployed and advanced during drilling. Running a liner while drilling (SWD) or liner drilling involves deploying a liner in the borehole as part of or connected to the drill string, and advancing the liner along with the drilling assembly while drilling a section of the borehole. Casing drilling (CwD) involves running a casing into the borehole using a drill bit and drilling the borehole using a casing string rotating the drill bit. This document describes embodiments in conjunction with liner drilling, but it should be understood that embodiments can be applied to various types of drilling operations in which the liner, casing, and / or other completion components are deployed using the drilling assembly or where an inner string is placed relative to the outer string.

[0029] In this embodiment, the drilling and completion assembly 20 is a tailpipe drilling assembly comprising an inner tubing string 30 and an outer tubing string 32. The outer tubing string includes fittings, such as a tailpipe 34, that are deployed and left downhole to isolate a section of formation from the borehole 14. The outer tubing string 32 may include conventional casing and tailpipe or any other fittings that may remain downhole and / or be cemented in place. The outer tubing string 32 may include other components, such as a tailpipe shoe 36 and a setting sleeve 38. The tailpipe shoe 36 may include a reamer bit.

[0030] The drilling and completion assembly 20 may include additional components to facilitate drilling and / or completion. For example, an opening device such as an expandable downhole reamer 39 may be included to increase the borehole size from the size of the drill bit 22 to a size that accommodates the outer tubing string 32. The inner tubing string 30 may include a steering device 40, such as a rotary steering assembly with a bending subassembly or a mud motor. Furthermore, the drilling and completion assembly 20 may include one or more of a variety of sensing devices. Examples of sensing devices include: temperature sensors, pressure sensors, fluid sensors, accelerometers, magnetometers, gamma resistivity tools, pulsed neutron tools, magnetic resonance sensors, acoustic tools, etc. For example, the inner tubing string may include a logging-while-drilling (LWD) and / or measurement-while-drilling (MWD) device 42. Device 42 may be assembled with the steering device 40 and the drill bit as, for example, a BHA.

[0031] Sensors or measuring devices may also be included in the ground equipment 24. For example, the ground equipment 24 includes a fluid pressure and / or flow rate sensor 48 for measuring the fluid flowing into and out of the borehole 14. The fluid pressure sensor can detect pressure changes in the fluid column in the borehole 14 for transmitting data in a mud pulse telemetry system.

[0032] In one embodiment, one or more downhole components and / or one or more surface components may communicate with and / or be controlled by a processor such as downhole processor 44 and / or surface processing unit 46. In one embodiment, surface processing unit 46 is configured as a surface control unit to control various parameters such as rotational speed, drilling pressure, and fluid flow parameters (e.g., pressure and flow rate). Surface processing unit 46 may include a surface computer, monitor, and memory. Surface processing unit 46 is configured to receive, transmit, process, and store data transmitted from downhole to surface (uplink) and / or from surface to downhole (downlink) via communication channels such as wired communication channels, mud pulse telemetry, acoustic telemetry, or electromagnetic telemetry.

[0033] One or more processing devices, such as processing unit 46 (and / or downhole processor 44), may be configured to perform functions such as: controlling the deployment of the inner tubing string 30 and / or outer tubing string 32; controlling drilling and steering; controlling the pumping of borehole fluids and / or cement injection; performing downhole measurements; transmitting and receiving data; processing measurement data; and extending and retracting the operation of the extendable downhole reamer and / or monitoring system 10. The various functions discussed herein may be performed by human operators, processing devices, or a combination of both.

[0034] Prior to tailpipe drilling operations, the system is assembled by installing the inner tubing string 30 inside the outer tubing string 32. First, the outer tubing string 32 is lowered into the borehole 14, with its upper end still attached to the surface (e.g., at the drilling rig). Then, the inner tubing string 30 is deployed and lowered into the borehole 14 and the outer tubing string 32 until attachment elements (such as landing splines) in the inner tubing string 30 engage landing structures (e.g., grooves, splines, etc.). Alternatively or additionally, markers (such as magnets or radioactive markers) in the outer tubing string 32 and corresponding sensors in the inner tubing string 30 may be deployed for position detection. At this point, the relative positions of the inner tubing string 30 and the outer tubing string 32 are determined. Once the relative position of the inner tubing string 30 to the outer tubing string 32 is determined, the position of the inner tubing string 30 is adjusted as needed to ensure proper engagement of the inner and outer tubing strings. This assembly process is completed by using a run-in tool including an extendable anchor to anchor the inner tubing string 30 in an anchor cavity within the outer tubing string 32 to engage the inner tubing string 30 with the outer tubing string 32. The drilling and completion assembly 20 can then be further advanced to the bottom of the borehole 14, and drilling can commence. The adjustment of the position of the inner tubing string 30 is performed by axially moving the inner tubing string 30 through the outer tubing string 32 in the uphole or downhole direction (e.g., lifting or running it into the borehole).

[0035] Proper positioning of the inner tubing string 30 is important for the efficient execution of various operations. Knowing the relative position of the inner tubing string 30 within the outer tubing string 32, structures can be properly engaged and manipulated downhole as intended by moving the inner tubing string 30 a defined distance from the marker assembly in the uphole or downhole direction to align the structures in the outer tubing string with their corresponding structures in the inner tubing string. Examples of structures or components that may rely on proper positioning include: anchoring modules, latching elements, packers, measuring tools, testing tools, expandable reamers, extendable stabilizers, anchoring elements, hanger initiation tools, liner drive subs, workover tools, milling tools, cutting tools, and / or communication devices. The relative position of the inner tubing string 30 to the outer tubing string 32 is determined by detecting the marker assembly in the outer tubing string 32. Knowing the position of the marker assembly in the outer tubing string 32, the positions of all other structures within the outer tubing string 32 are known, as the distances of these structures from the marker assembly's position are known. The distance between the lowest end of the inner column 30 and the corresponding structure within the inner column 30 is also known. Therefore, using the inner column 30 to mark the marking assembly in the outer column 32 calibrates the relative positions of the inner and outer columns and allows for the alignment of a specific structure in the inner column 30 with a specific structure in the outer column 32.

[0036] Aligning a specific structure in the outer tubing string 32 with a corresponding specific structure in the inner tubing string 30 may include placing the inner tubing string 30 within the outer tubing string 32 such that the BHA's fast-spinning components (e.g., components below the mud motor) are located outside the liner 34 and below the reamer in the liner shoe 36, so as not to damage the reamer or the inner tubing string 30 due to interaction between the reamer and the inner tubing string 30. Adjusting the relative position of the inner and outer tubing strings to each other can be achieved by extending the inner tubing string 30 by adding inner tubing string components or shortening the inner tubing string 30 by removing inner tubing string components (e.g., drill joints). For example, a drill joint is approximately 30 feet (about 9 m) long, so adding or removing a drill joint extends or shortens the inner tubing string 30 by approximately 30 feet. If adjusting the relative positions of the inner and outer tubing strings requires a length adjustment different from that of the standard drilling joint, joints of different lengths (e.g., pup joints) can be deployed, such as joints with lengths of approximately 0.5m to approximately 1m, approximately 0.5m to approximately 3m, approximately 0.5m to approximately 5m, or approximately 0.5m to approximately 9m.

[0037] refer to Figure 2In one embodiment, the outer tubing 32 includes a positioning assembly 50 or connected to it, the positioning assembly including a sacrificial stop member 52 disposed relative to and positioned at a known location (referred to as a “marked location”) within the outer tubing 32. The positioning assembly 50 allows determination of the relative positions of the inner and outer tubing sections relative to each other. This determination is generally referred to as “marking.” Therefore, the positioning assembly 50 is also referred to as the marking assembly 50. In one embodiment, the marking assembly 50 and / or the stop member 52 may be fixedly disposed within the outer tubing 32. In another embodiment, the stop member 52 and / or the marking assembly 50 may be loosely disposed within the outer tubing 32 such that the stop member 52 and / or the marking assembly 50 are movable relative to the outer tubing 32. The stop member 52 and / or the marking assembly 50 may be disposed in a recess that allows small relative movements between the outer tubing 32 and the stop member 52 with respect to axial, lateral, and / or rotational movement.

[0038] The blocking member 52 extends radially inward from the outer tubing string 32 such that the drill bit 22 contacts the blocking member 52 when fully deployed. The relative positions of the outer and inner tubing strings can be determined when it is detected that the drill bit 22 has contacted, been blocked, or obstructed by the blocking member 52. The blocking member 52 and / or other position-determining components or marking assemblies 50 can be positioned at any suitable location along the outer tubing string 32, such as in or near the stern shoe 36, or near the downhole or lower end of the stern pipe 34.

[0039] In one embodiment, the position of the blocking member 52 in the outer tube column 32 can be defined as a reference position (also known as a marked position). When the inner tube column 30 encounters the blocking member 52, the inner tube column 30 is considered to be in the reference position (also known as the marked position). For example, the reference position or marked position is defined as the zero-meter (m) relative position (marked position) between the inner and outer tube columns. When the inner tube column 30 encounters the blocking member 52 with its lowermost end, the inner tube column 30 is considered to be at the marked position in the outer tube column 32 (i.e., for the purpose of aligning the structures, the positions of the inner tube column 30 and the outer tube column 32 are considered to be approximately the same). Given that the distances of all outer tube column structures in the outer tube column 32 from the marked position (zero-m position) and the distances of all inner tube column structures in the inner tube column 30 from the lowermost end of the inner tube column 30 are known, it is permissible to align a specific structure in the outer tube column 32 with a corresponding specific structure in the inner tube column 30 by moving the inner tube column 30 to a distance that aligns a specific structure in the outer tube column 32 with a corresponding specific structure in the inner tube column 30. Therefore, the relative positions of the outer and inner tubing strings are calibrated by using the inner tubing string 30 to contact the blocking member 52 in the outer tubing string 32. The ability to align a specific outer tubing string structure with a specific inner tubing string structure enables downhole operations associated with that specific inner and outer tubing string structure, such as engaging the anchor in the inner tubing string 30 with a recess (e.g., an anchor cavity) in the outer tubing string 32. The inner tubing string 30 will be moved a distance that aligns the corresponding specific inner tubing string structure with the specific outer tubing string structure, either in the surface direction (towards the surface) or in the downhole direction (further into the borehole).

[0040] The distance moved in the surface direction can be defined as a negative distance (e.g., -3m), and the distance moved in the downhole direction can be defined as a positive distance (e.g., +3m). For example, a specific structure (e.g., an anchor cavity) in the outer tubing string is located -5m from the marking assembly in the outer tubing string 32 (surface direction). A corresponding specific structure (e.g., an anchor) in the inner tubing string 30 is located -2m from the lowest end of the inner tubing string. When the inner tubing string 30 encounters the blocking member 52 in the marking assembly (marking position), the inner tubing string 30 will be moved -3m from the marking position (surface direction) to align the specific structure (e.g., the anchor cavity) in the outer tubing string with the specific corresponding structure (e.g., the anchor) in the inner tubing string 30. When the specific structure in the outer tubing string 32 is aligned with the specific corresponding structure in the inner tubing string 30, the operation of engaging these two structures can be performed. The engagement operation may involve extending the anchor in the inner string 30 into the anchor cavity in the outer string 32 to connect the outer string 32 to the inner string 30 with respect to weight and / or torque transmission (tooling). With the inner and outer strings connected and aligned, downhole operations can commence, such as drilling a borehole using the combined inner string 30 (drill string) and the outer string 32 (tailpipe) with a reaming bit at its lower end. In one embodiment, the lowermost end of the inner string 30 may be located within the drill bit 22 connected to the inner string 30. In another embodiment, the lowermost end of the inner string 30 may be a fitting (e.g., a string pipe), a fishing tool, a milling tool, a workover tool, a bullnose, a logging cable tool, or the like.

[0041] For example, if the marking assembly 50 is prematurely crushed, multiple marking assemblies 50 can be arranged within the outer tubing 32 to provide redundancy. For example, upper and lower marking assemblies can be arranged axially along the outer tubing 32 (e.g., in shoe 36). If the upper stop of the upper marking assembly is unintentionally crushed (e.g., due to inappropriate tripping speeds), the lower stop can be used for marking and length adjustment.

[0042] Various marker components 50 may also differ in shape, material, and sub-components, and may require different amounts of force to crush. Multiple marker components 50 may also be used to detect more than one location of interest, such as drilling location, cement bond location, reaming location, etc. In one embodiment, a first marker component 50 may be used to indicate the approach of a second marker component 50. The first marker component 50 may be a warning marker component. The second marker component 50 may be a calibration marker component used to calibrate the relative positions of the inner and outer tubing strings. When the first marker component 50 is struck and crushed, a change in the weight of drill bit (WOB) measurement at the surface can be observed. When a change (reduction) in WOB is observed due to the crushing of the first marker component 50, the tripping speed can be reduced to slowly approach the second marker component 50 to safely detect its position without unintentionally crushing it. When the second marker component 50 is struck, another change in the WOB measurement can be detected at the surface. At this point, the relative positions of the inner and outer tubing strings are known (calibration of relative positions), and alignment of the inner tubing string 30 and the outer tubing string 32 can begin. It should be mentioned that, in the case of WOB changes due to impact on the first marking component 50, the relative positions of the inner and outer tubing can be calibrated before impact on the second marking component 50.

[0043] The reduced tripping speed near the second marker assembly 50 can be from about 1 m / min to about 2 m / min. In another embodiment, the tripping speed near the second marker assembly 50 can be from about 1 m / min to about 5 m / min. In yet another embodiment, the tripping speed near the second marker assembly 50 can be from about 1 m / min to about 10 m / min. Drilling pressure can be measured by a drilling pressure measuring device. The drilling pressure measuring device monitors hook load sensors or measures downhole drilling pressure using a strain gauge. The downhole drilling pressure measurements are transmitted to the surface. Surface processing unit 46 ( Figure 2 This may include a processor configured to monitor the measured drill pressure data and detect changes in drill pressure on markers indicating the marking component. Drill pressure changes may be negative or positive peaks in the drill pressure data.

[0044] The blocking member 52 is sacrificial because it can be broken, shattered, or otherwise crushed by forces applied to it. In one embodiment, the blocking member 52 is made of a sufficiently brittle material such that sufficient axial force on it causes it to break into small enough fragments to circulate with the borehole fluid without significantly restricting fluid flow or interfering with other components in the borehole. Examples of such materials include cement, ceramics, plastics, rock, porcelain, building stone, and glass. It should be noted that due to the brittleness of the material, the blocking member 52 can be crushed without drilling through it or rotating the drill bit 22.

[0045] In an alternative embodiment, the blocking member 52 is made of an elastic material to dampen the initial impact when struck by the drill bit 22. The elastic material may break into fragments or be configured as individual components. The components or fragments may be small enough to be circulated out of the borehole by borehole fluid, and / or once the system 10 is assembled, lowered to the bottom, and the drilling process has begun, the drill bit 22 may grind the component or fragment into smaller pieces. Examples of such blocking members include ropes or nets made of nylon, Kevlar, or other suitable materials.

[0046] In another embodiment, the blocking member 52 is made of a ductile material that can be sheared during the application of axial force by the drill bit 22. In a later state, as rotation of the drill string is established, the blocking member 52 can be further broken, fragmented, crushed, or ground into pieces small enough to circulate to the ground with the borehole fluid during re-establishment of circulation. Examples of such materials include aluminum, plastic, brass, etc.

[0047] In another embodiment, the blocking member 52 is made of a robust material such as steel, but is perforated or otherwise configured to break into fragments or deform to allow the inner tubular column 30 to advance. For example, the blocking member 52 may be made of a perforated sheet of metal that can be bent radially outward or otherwise deformed once the axial force applied by the drill bit exceeds a certain threshold force.

[0048] In one embodiment, the blocking member 52 includes an opening, or is otherwise configured to allow drilling fluid to circulate through the outer string 32, for example, as the inner string 30 is advanced to the marking assembly 50. For example, the blocking member 52 may be a disc, cylinder, or other annular member with a central opening that allows fluid to flow through the blocking member 52 before engagement with the drill bit 22.

[0049] The blocking member 52 may include multiple discs, such as two discs. Using more than one disc allows adjustment of the axial force (threshold force) required to crush and / or displace the blocking member 52. The discs may be, for example, about 40 mm to about 45 mm thick, and for a 7-inch liner, may have a diameter of about 166 mm. In the case where the blocking member 52 includes two discs, each of the two discs may be about 20 mm to about 22.5 mm thick. Generally, the diameter of the discs is limited by the diameter of the liner 34 or the diameter of the recess in the outer casing 32. The thickness of the discs is determined by the material of the discs, the drill bit type, and the desired axial force (axial threshold force) required to crush the discs. The discs should withstand tripping operations. Therefore, the axial force required to crush the discs should be chosen to be not too small to avoid unintentionally crushing the discs during tripping operations. Experiments have shown that disc-shaped objects suitable for crushing under axial threshold forces corresponding to approximately ten tons of WOB provide optimal operating characteristics.

[0050] The central opening of the disk (e.g., central opening 55 discussed below) may have a diameter of approximately 50% of the outer diameter of the disk. For example, for a disk with a diameter of approximately 166 mm, the central opening may be approximately 83 mm. In an alternative embodiment, the diameter of the central opening may be less than 50% of the outer diameter of the disk, for example, approximately 40% to approximately 49%, or approximately 30% to approximately 49%. In another embodiment, the diameter of the central opening may be greater than 50% of the outer diameter of the disk, for example, approximately 51% to approximately 60%, or approximately 51% to approximately 70%.

[0051] The disc-shaped object may include more than one opening. In one embodiment, the disc-shaped object may include one or more openings eccentrically positioned within the disc-shaped object. The disc-shaped object may be oriented in the outer column 32 substantially perpendicular to the longitudinal axis A. In an alternative embodiment, the orientation of the disc-shaped object may be at an angle other than 90° to the longitudinal axis A, for example, about 95 degrees to about 100 degrees (or about 80 degrees to about 85 degrees), or about 95 degrees to about 110 degrees (or about 70 degrees to about 85 degrees). The disc-shaped object may have a gap of about 1 mm between each side and the wall of the recess (the diameter of the disc-shaped object may be about 2 mm smaller than the inner diameter of the recess).

[0052] For example, the blocking member 52 may include one or more individual components having the shape of a rod, bar, or column (etc.), each of which is positioned perpendicular to or at least at an angle to the longitudinal axis of the outer tube 32. The individual components may be individually small enough to be recycled to the ground once sheared or broken from the marked location. The number of individual components included in the blocking member 52 can be selected to adjust the amount of axial force (marking force) required to displace the blocking member 52.

[0053] In an alternative embodiment, the blocking component 52 is a solid disc without openings and is sealed inside the stern shoe 36, or otherwise configured to prevent formation fluids or gases from entering the outer tubing 32 from below the marker assembly 50 in the event of a well control situation (e.g., a well kick) during the assembly of the stern drilling system 10. This reduces or eliminates the need for additional well control equipment to seal the stern inner diameter on the ground.

[0054] Figure 2 and Figure 3 An example of a marking assembly 50 is depicted, wherein the blocking component is an annular component, such as a glass disc 54. The disc 54 has a central opening 55 (in... Figure 3 (As shown in the figure) to allow drilling fluid to enter the outer tubing 32 when it is lowered into the borehole, thereby facilitating the drilling process.

[0055] The disc-shaped member 54 (or other blocking member) can be positioned at the marked location on the outer post 32 via any suitable fixing mechanism (also referred to as a support structure). For example, the disc-shaped member 54 is inserted into a recess, shoulder, or other feature of the outer post 32. For example, the glass disc-shaped member 54 is fixed within a recess 56 formed in the connection between the stern shoe 36 and the reamer stop 59 (which has a reamer bit (not shown) at its bottom end) (e.g., a male-female connection, a threaded connection, or a threaded connection having an outer shoulder 57a for supporting the blocking member). The outer shoulder 57a can be located in the stern shoe 36. A lower shoulder 57b, opposite the outer shoulder 57a, can be located on the upper end of the reamer stop 59. The upper end of the reamer short 59 may include a male threaded connection, while the lower end of the stern shoe 36 may include a female threaded connection. In an alternative embodiment, the upper end of the reamer short 59 may include a female threaded connection, and the lower end of the stern shoe 36 may include a male threaded connection. In an alternative configuration, the blocking member 52 may be mounted inside the outer tube 32 by press fitting, adhesive, radial bolts or screws, or other suitable fastening measures or components. In another embodiment, the blocking member 52 in the stern tube 34 may be supported by components other than the reamer short (e.g., a dedicated retaining sleeve). The blocking member 52 may be loosely disposed (including axial clearance) in the recess 56, or may be fixed between shoulders 57a and 57b without axial clearance. In yet another embodiment, the fixation of the blocking member 52 may include a lateral clearance in a direction perpendicular to the longitudinal axis A of the stern tube 34. Figure 2 The support structure shown includes a recess 56, an outer shoulder 57a, and a lower shoulder 57b.

[0056] The blocking component (or components) 52 may have various shapes, such as rods, bars, or columns, positioned perpendicular to or at least at an angle to the longitudinal axis of the outer tube 32. Such blocking components 52 may be attached to the outer tube 32 by threads, bolts, welding, adhesive bonding, or other suitable fastening means. The fastening of the rod, bar, or column blocking component 52 may be applied through the wall of the outer tube 32 and perpendicular to or at least at an angle to the longitudinal axis A of the outer tube 32.

[0057] In one embodiment, the marking assembly 50 includes a force distribution member 58, such as a plastic disc, disposed on the surface of the glass disc 54 (or other blocking member). The force distribution member 58 may be made of any suitable material, such as a polymeric material (e.g., polyetheretherketone (PEEK)), rubber, wood, cork, plastic, composite material, or other material with less brittleness than the disc 54. The force distribution member 58 may be disposed on the uphole side of the disc 54 or typically on the side of the disc facing the adjacent inner tubing 30.

[0058] In one embodiment, the force distribution member 58 is configured such that when the disc 54 is crushed, the member 58 breaks into a plurality of segments 60. The segments 60 are selected to be small enough that they can circulate with the drilling fluid. The segments 60 may be defined by grooves or notches 62 or other weakening features (also referred to as predetermined fracturing points).

[0059] The marking assembly 50 may include components or materials configured to reduce impact loads on the disk 54 and / or component 58, for example, to prevent premature breakage upon impact with the marking assembly 50. In one embodiment, the marking assembly 50 includes one or more materials, such as rubber, polymer materials, or any other flexible material (referred to as an impact damping component), capable of absorbing and damping impacts. The impact damping component may be disposed on any surface of the disk 54 as needed and may be configured as a layer or discrete elements. The impact damping component may include a single element or multiple elements.

[0060] For example, such as Figure 4As shown, the impact damping component includes an impact damping element 64 disposed between the force distribution component 58 and the disc-shaped member 54. In one embodiment, the impact damping element 64 may be located between the blocking component 52 and the force distribution component 58. The impact damping element 64 may be located on the uphole side of the blocking component 52 (upper impact damping element). The impact damping element 64 may be formed in layers, meshes, or grids. In alternative embodiments, the impact damping element 64 may take the form of multiple individual elements, such as knots, pins, columns, balls, etc. Although multiple individual elements 64 are shown, the impact damping component is not limited to this and may be a single element or multiple elements located at various locations.

[0061] In another embodiment, the impact damping component may be located on the downhole side of the blocking component 52 (e.g., as a lower impact damping element 65). The lower impact damping element 65 can compensate for manufacturing tolerances and dampen impacts on the disc-shaped object 54. The lower impact damping element 65 on the downhole side of the blocking component 52 may take the form of a gasket, washer, grommets, O-rings, washers, or flexible tubing. The lower impact damping element 65 may cover the entire circle (360°) or only a portion of the entire circle (arc). If the lower impact damping element 65 is a flexible tubing (e.g., a rubber hose) or an O-ring, the cross-section of the tubing or O-ring may be from about 5 mm to about 10 mm. In another embodiment, the cross-section of the O-ring or tubing may be from about 6 mm to about 8 mm.

[0062] The impact damping component may include a lateral impact damping element 66, which may be disposed on the outer circumference of the disc 54 and in a portion of the recess 56 oriented substantially parallel to the longitudinal axis A. The lateral impact damping element 66 dampens lateral impacts to prevent premature displacement or shattering of the blocking component 52. In one embodiment, the lower impact damping element 65 may include a downhole sealing element such as an O-ring to abut against the lower shoulder 57b of the recess 56. Figure 2 A sealing disc 54. In another embodiment, the downhole sealing element may be an element independent of the lower impact damping element 65. The downhole sealing element may be made of rubber, polymer material, or any other flexible material. In one embodiment, an uphole sealing element (not shown), such as an O-ring, is included on the uphole side of the marking assembly 50 to abut against the outer shoulder 57a of the recess 56. Figure 2 A sealing disc 54 can be advantageous. The wellhead sealing element can take the form of an O-ring or a flexible tube and can be made of rubber, polymer materials, or any other flexible material. The sealing element can be used in a marking assembly 50 comprising a solid disc without a central bore to isolate the conduit in the tailpipe 34 from the borehole fluid.

[0063] Figure 5A method 70 for drilling and completing a borehole of a certain length is shown. In one embodiment, method 70 involves tailpipe drilling, but is not limited thereto, as the method can be used in any situation where it is desired to temporarily block the downhole string or components.

[0064] Method 70 is described with reference to System 10, but method 70 can be used in conjunction with any suitable type of apparatus or system, where the markings are desired by such suitable type of apparatus or system, or where the marking components or blocking parts are useful for such suitable type of apparatus or system. Method 70 includes one or more steps represented by blocks 71 to 77. In one embodiment, method 70 includes performing all blocks 71 to 77 in the stated order. However, certain steps may be omitted, additional steps may be added, and / or the order of the steps may be changed.

[0065] For illustrative purposes, combined with Figures 6 to 9 The following example of the components of the tailpipe drilling system is used to discuss method 70. Figures 6 to 9 Examples of inner tubular column 30 and outer tubular column 32 are depicted, and the various stages of method 70 are shown.

[0066] Figure 6 The initial stage in which the outer tubing 32 is deployed into the borehole 14 prior to the deployment of the inner tubing 30 is depicted. Figure 7 The stages in which the inner tube column 30 is deployed and advanced until the inner tube column 30 contacts or otherwise engages the marking assembly 50 are depicted. Figure 8 The stages in which drilling pressure and associated forces are increased to crush or otherwise pulverize the blocking component 52 are depicted. Figure 9 It depicts a stage in which a portion of the inner tubing 30 is advanced beyond the outer tubing 32 in preparation for drilling.

[0067] At frame 71, the outer tubing string 32 is deployed to the selected borehole location or depth. Note that "depth" refers to the distance along borehole 14 from the ground surface (measured depth (MD)). Alternatively, the depth may correspond to the true vertical depth (TVD), which is the shortest distance between a specific location in borehole 14 and the ground surface, or the vertical distance from a specific location in the borehole to the ground surface. The measured depth of the borehole or the measured depth of components within the borehole is typically measured by adding the lengths of the components constituting the downhole string as the downhole tubing string is run into the borehole (such as when a drill string is run). The measured depth of the borehole or the measured depth of components within the borehole can be performed using a depth measuring device. The depth measuring device includes a processor that monitors signals from a winch encoder. Winch encoders are well known and will not be described further herein. In addition to measuring the depth, the depth measuring device is also configured to measure the distance (axial distance) that the inner tubing 30 moves inside the outer tubing 32 in order to adjust the relative position between the inner and outer tubings so as to align the structure in the outer tubing 32 with the corresponding structure in the inner tubing 30.

[0068] For example, such as Figure 6 As shown, the outer casing string 32 is deployed downhole and secured to the surface via slips 80. The outer casing string may be run into the main casing 33. The outer casing string 32 includes a liner 34, a liner shoe 36, and a marker assembly 50. In this example, the blocking member 52 is a glass disc capable of withstanding forces in the downhole direction (e.g., applied by the drill bit or other crushing device) below a selected axial threshold force. For example, the axial threshold force corresponds to approximately three tons of borehole weight (WOB), or approximately six tons of borehole weight, or approximately ten tons of axial force, or any other threshold. The blocking member 52 may be glass or any other material with sufficient brittleness (e.g., ceramic or cement) such that the blocking member 52 is crushed and / or broken into pieces small enough to be circulated by borehole fluid without clogging the borehole or downhole components or otherwise interfering with the normal operation of downhole components. The blocking member 52 may be disposed in a liner shoe 36 particularly suitable for liner drilling. The liner shoe 36 may include a stabilizer 35 with stabilizer blades. The liner shoe 36 includes an increased wall thickness compared to a standard liner. The liner 34 may have, for example, an outer diameter of about 7 inches, and the liner shoe 36 may have an outer diameter of about 8.5 inches. The inner diameters of the liner 34, liner shoe 36, and reamer bit may be about 6 inches. In one embodiment, the liner shoe 36 includes a connection at the downhole end for connecting to the reamer bit (male-female thread connection). In a non-limiting example, the connection may be as follows: Figure 2 The cylindrical connection shown in the figure. The connection between the stern shoe 36 and the reamer can be used to secure the blocking member 52 in the outer tube 32. The blocking member 52 can be located in the stern shoe 36, at or near the stabilizer 35.

[0069] At frame 72, inner column 30 is deployed via outer column. Figure 7 In the example, the inner string 30 is a drill string that is deployed using a drilling rig equipped with a lifting system and a top drive system 82 or other suitable equipment. The inner string 30 includes, for example, string segments 84 (such as sub sections or segments) and BHA 86. The inner string 30 is not limited to this and can be made of any suitable components, such as logging cables or coiled tubing.

[0070] For example, refer to Figure 7 The BHA 86 includes a drill bit and steering system (such as a steerable drill bit 22 connected to a steering unit 40) and an LWD / MWD unit 42. Additional drill bits and / or other tamping devices may be included, such as a reamer 88 on the stern shoe 36 and / or a hole-opening device 90, which includes an extendable downhole reamer 92. The hole-opening device 90 and the steerable drill bit 22 may be driven by a downhole motor (mud motor) 94 and / or from the surface via, for example, a top drive unit 82. Electricity may be supplied to the BHA 86, and communication may be transmitted using a communication and power module 96, which may be connected to a battery short 98 and / or a surface unit (e.g., via a cable or logging cable).

[0071] At frame 73, the inner tubing 30 is advanced through the outer tubing 32 until the drill bit or other component of the inner tubing 30 engages the blocking component 52. The component may "engage" the blocking component by: direct contact with the blocking component 52, contact with another component of the marking assembly 50 that transmits force to the blocking component 52, or any other means by which force is applied to the blocking component 52.

[0072] Refer again Figure 7 For example, the initially selected WOB is used to advance the inner tubing 30. When the guide drill bit 22 contacts the blocking member 52 or is otherwise blocked by the blocking member, it can be detected immediately at the ground.

[0073] At frame 74, the depth or position of the guide drill bit 22 (relative to the outer tubing 32) is known. The measured depth of the guide drill bit is also known. The relative positions of other components of the inner tubing 30 (such as the hole-opening device 90 and the motor 94) are also known. The operator and / or processing equipment determine whether the inner tubing 30 is properly positioned based on the relative positions and make any length or position adjustments as needed.

[0074] At frame 75, the force on the blocking member 52 is increased above the axial threshold force to crush, break, or otherwise pulverize the blocking device 52. For example, refer to Figure 8When the drilling pressure increases to exceed the threshold weight (e.g., about three tons), this crushes the stopper 52. Fluid circulation can then be used to remove the crushed fragments of the stopper 52. Alternatively, the crushed fragments of the stopper 52 may remain in the borehole and may be circulated out of the borehole and / or further crushed during drilling.

[0075] At frame 76, once the position of the inner tubing string 30 has been confirmed and / or adjusted, an assembly process is performed to prepare the inner tubing string 30 and drilling assembly 20 for drilling. The inner tubing string 30 is advanced so that the guide bit 22 passes over (below) the outer tubing string 32 and is in the starting position for drilling. For example, refer to... Figure 9 The inner tubing string 30 advances past the stern shoe 36 until the motor 94 engages with or is adjacent to the stern shoe 36, and the reamer 90 is located outside the stern pipe 34 and the stern shoe 36. The downhole reamer 92 can then be extended radially, and the drilling assembly of the inner tubing string 30 can be rotated to perform drilling operations.

[0076] At frame 77, after the assembly process is completed, the entire drilling and completion assembly 20 can be advanced to the bottom of borehole 14 to begin drilling operations.

[0077] Method 70 can be executed automatically without human intervention. The processor in the surface processing unit 46 controls the hoisting system in the drilling rig located on the surface, which controls the movement of the inner tubing string 30 within the outer tubing string 32. The processor can use a drill pressure measurement device to monitor drill pressure data to detect the inner tubing string engaging the blocking member 52. The processor can calibrate the relative positions (marking positions) of the inner and outer tubing strings and can increase the axial force on the blocking member 52 to crush it. The processor can use a depth measurement device to adjust the relative positions of the inner and outer tubing strings. The processor can initiate downhole operations, such as using a running tool to connect the inner tubing string to the outer tubing string and initiating drilling using the inner and outer tubing strings.

[0078] The following are some of the aforementioned publicly disclosed implementation schemes:

[0079] Implementation Scheme 1: An apparatus for determining the position of an inner tubing string in an outer tubing string of a downhole system, the apparatus comprising: an axis parallel to the longitudinal axis of the inner tubing string; a marking assembly disposed at a marking location in the outer tubing string, the outer tubing string being configured to be deployed into a borehole in a subsurface area, the inner tubing string being configured to advance through the outer tubing string, the marking assembly comprising: a blocking member configured to impede axial movement of the inner tubing string through the outer tubing string at the marking location, the blocking member being configured to displace in response to an axial force applied to the blocking member by the inner tubing string to allow the inner tubing string to advance axially beyond the marking assembly.

[0080] Implementation Scheme 2: According to any existing implementation scheme, the device further includes a depth measuring device configured to measure the axial distance along the axis by which the inner tube column moves relative to the outer tube column.

[0081] Implementation Scheme 3: The device according to any existing implementation scheme further includes a drill pressure measuring device configured to measure drill pressure to detect the marking of the inner tubing against the blocking member.

[0082] Implementation Scheme 4: The device according to any existing implementation scheme, wherein the blocking component is made of at least one of cement, plastic and glass.

[0083] Implementation Scheme 5: The device according to any existing implementation scheme, wherein the blocking member is connected to a support structure of the outer tube column, the support structure being configured to prevent axial movement of the blocking member prior to displacement of the blocking member.

[0084] Implementation Scheme 6: The device according to any existing implementation scheme, wherein the blocking member is configured to crush in response to the axial force exceeding an axial threshold force.

[0085] Implementation Scheme 7: The device according to any existing embodiment, wherein the blocking member is made of a material configured to hold the inner tube at the marked position until the axial threshold force applied by the inner tube, the material being brittle such that the axial threshold force causes the blocking member to shatter.

[0086] Implementation Scheme 8: The device according to any existing embodiment, wherein the blocking member is made of a material configured to hold the inner tube at the marked position until the axial threshold force applied by the inner tube, and deforms and displaces in response to the axial threshold force to allow the inner tube to advance axially.

[0087] Implementation Scheme 9: The device according to any existing implementation scheme, wherein the blocking component is configured to allow fluid to flow through the outer tube column.

[0088] Implementation Scheme 10: The device according to any existing implementation scheme, wherein the blocking component is configured to prevent fluid from flowing through the outer tube column.

[0089] Implementation Scheme 11: The device according to any existing implementation scheme, wherein the marking assembly includes a sealing element.

[0090] Implementation Scheme 12: The device according to any existing embodiment further includes a force distribution member disposed on the surface of the blocking member, the force distribution member being configured to disperse the axial force applied by the inner tube column when engaging with the marking assembly.

[0091] Implementation Scheme 13: The device according to any existing implementation scheme further includes at least one of an additional layer and a separation element, the additional layer and the separation element being made of at least one material different from the material constituting the blocking member, the at least one material being configured to dampen impact loads when the inner tube column contacts the marking assembly.

[0092] Implementation Scheme 14: The device according to any existing implementation scheme, wherein the force distribution component comprises multiple segments and is made of a polymer material.

[0093] Implementation Scheme 15: The device according to any existing implementation scheme, wherein the blocking component includes an opening.

[0094] Implementation Scheme 16: A method for determining the position of an inner tubing string in an outer tubing string of a downhole system, the method comprising: deploying the outer tubing string into a borehole in a subsurface area, the outer tubing string including a marking assembly including a blocking member disposed at a marked location in the outer tubing string; deploying the inner tubing string and advancing the inner tubing string until the inner tubing string engages the blocking member, the blocking member impeding axial movement of the inner tubing string at the marked location; performing measurements to determine the position of the inner tubing string relative to the outer tubing string; displacing the blocking member by applying an axial force from the inner tubing string to the blocking member to allow the inner tubing string to advance axially beyond the marking assembly; and performing downhole operations based on the measurements.

[0095] Implementation Scheme 17: The method according to any existing implementation scheme, the method further comprising: adjusting the position of the inner tubing string relative to the outer tubing string prior to the downhole operation.

[0096] Implementation Scheme 18: The method according to any existing implementation scheme, the method further comprising: measuring drilling pressure to detect the marked position.

[0097] Implementation Scheme 19: The method according to any existing implementation scheme, wherein displacing the blocking member includes: crushing the blocking member by applying an axial force exceeding an axial threshold force.

[0098] Implementation Scheme 20: The method according to any existing implementation scheme, the method further comprising: circulating the crushed blocking component out of the borehole.

[0099] In the context of describing the invention (particularly in the context of the appended claims), the terms “an,” “a,” and “the,” and similar designations, should be interpreted to cover both the singular and plural, unless otherwise specified herein or clearly contradicted by the context. Furthermore, it should be noted that the terms “first,” “second,” etc., used herein do not indicate any order, quantity, or importance, but are used to distinguish one element from another. The modifier “about,” used in conjunction with quantity, includes the stated value and has a meaning determined by the context (e.g., it includes the degree of error associated with a particular quantity of measurement).

[0100] The teachings of this disclosure can be applied to a variety of well operations. These operations may involve treating a formation, fluids residing in the formation, the wellbore, and / or equipment within the wellbore, such as production tubing, with one or more treatment agents. Treatment agents can be in the form of liquids, gases, solids, semi-solids, and mixtures thereof. Exemplary treatment agents include, but are not limited to, fracturing fluids, acids, steam, water, brine, corrosion inhibitors, binders, permeability modifiers, drilling mud, emulsifiers, demulsifiers, tracers, flow improvers, etc. Exemplary well operations include, but are not limited to, hydraulic fracturing, production enhancement, tracer injection, cleaning, acidizing, steam injection, water injection, cementing, etc.

[0101] Although the invention has been described with reference to one or more exemplary embodiments, those skilled in the art will understand that various changes can be made and equivalents can be substituted for elements therein without departing from the scope of the invention. Furthermore, many modifications can be made to adapt particular situations or materials to the teachings of the invention without departing from the basic scope of the invention. Therefore, it is contemplated that the invention is not limited to the specific embodiments disclosed as the best mode contemplated for carrying out the invention, but rather that the invention will include all embodiments falling within the scope of the claims. Additionally, exemplary embodiments of the invention have been disclosed in the drawings and detailed descriptions, and although specific terminology has been used, it is used in a general and descriptive sense only, and not for limiting purposes, unless otherwise specified, and therefore the scope of the invention is not limited thereto.

Claims

1. An apparatus for determining the position of an inner tubing string (30) of a downhole system (10) within an outer tubing string (32), the apparatus comprising: The axis is parallel to the longitudinal axis of the inner tube (30); A marking assembly (50) disposed at a marking position in the outer tubing (32), the outer tubing (32) being configured to be deployed into a borehole (14) in an underground area, the inner tubing (30) being configured to advance through the outer tubing (32), the marking assembly (50) comprising: A blocking member (52), made of a brittle material and disposed in the outer tubing, is configured to impede axial movement of the inner tubing (30) through the outer tubing (32) at the marked position. The blocking member (52) includes an uphole side and a downhole side. The blocking member (52) is configured to displace in response to an axial force applied to the blocking member (52) by the inner tubing (30) to allow the inner tubing (30) to advance axially beyond the marked assembly (50). A force distribution component (58) configured to disperse the axial force applied by the inner tubing (30) upon engagement with the marking assembly (50), the force distribution component (58) being disposed on the uphole side of the blocking component (52), the force distribution component (58) being made of a brittle material, wherein the brittleness of the material used to make the force distribution component (58) is less than the brittleness of the material used to make the blocking component (52); and An impact damping component is configured to dampen the impact of the inner tube column on the blocking component (52). The impact damping component is disposed between the blocking component and the force distribution component. The impact damping component is made of a flexible material different from the material used to manufacture the blocking component.

2. The device according to claim 1, further comprising a depth measuring device configured to measure an axial distance along the axis along which the inner tube (30) moves relative to the outer tube (32).

3. The apparatus of claim 1, further comprising a drill pressure measuring device configured to measure drill pressure to detect markings made by the inner tubing (30) on the blocking member (52).

4. The device according to claim 1, wherein the blocking component (52) is made of at least one of cement, plastic and glass.

5. The device according to claim 1, wherein the blocking member (52) is connected to a support structure of the outer column (32), the support structure being configured to prevent axial movement of the blocking member (52) prior to displacement of the blocking member (52).

6. The device according to claim 1, wherein the blocking member (52) is configured to crush in response to the axial force exceeding an axial threshold force.

7. The device according to claim 6, wherein the blocking member (52) is made of a material configured to hold the inner tube (30) at the marked position until the axial threshold force applied by the inner tube (30), the brittleness of the material used to make the blocking member causing the axial threshold force to cause the blocking member (52) to shatter.

8. The device according to claim 1, wherein the force distribution component (58) comprises a plurality of segments (60) and is made of a polymer material.

9. A method for determining the position of an inner tubing string (30) of a downhole system (10) within an outer tubing string (32) using the apparatus according to any one of claims 1-8, the method comprising: The outer pipe string (32) is deployed into a borehole (14) in an underground area. The outer pipe string (32) includes a marking assembly (50) which includes a blocking member (52) disposed at a marking position in the outer pipe string (32). Deploy the inner tube column (30) and advance the inner tube column (30) until the inner tube column (30) engages the blocking member (52), the blocking member (52) impeding axial movement of the inner tube column (30) at the marked position; Perform measurements to determine the position of the inner tubing (30) relative to the outer tubing (32); The blocking member (52) is displaced by applying an axial force from the inner tube (30) to the blocking member (52) to allow the inner tube (30) to advance axially beyond the marking assembly (50); and Downhole operations are performed based on the measurements.

10. The method according to claim 9, further comprising: Before the downhole operation, adjust the position of the inner tubing string (30) relative to the outer tubing string (32).

11. The method according to claim 9, further comprising: Measure the drilling pressure to detect the marked location.

12. The method of claim 9, wherein displacing the blocking member (52) comprises: The blocking component (52) is crushed by applying an axial force exceeding the axial threshold force.

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