Systems and Methods for Data Acquisition From Outside a Well Casing

Abstract

Subsurface instrumentation of newly created wellbores will enable enhanced long-term wellbore integrity monitoring, improved induced seismicity measurements, deep flow control applications, novel scientific evaluation tools, carbon sequestration monitoring, and many national security applications. The system minimizes interruption or change of practice to existing borehole completions techniques. The systems and methods utilize an instrumented casing collar and / or centralizer approach.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims priority to U.S. Provisional Application No. 63 / 748,231, filed on Jan. 22, 2025, entitled “Systems and Methods for Data Acquisition From Outside a Well Casing,” the entirety of which is incorporated herein by reference.GOVERNMENT INTEREST STATEMENT

[0002] This invention was made with Government support under Contract No. DE-NA0003525 awarded by the United States Department of Energy / National Nuclear Security Administration. The U.S. Government has certain rights in this invention.FIELD OF THE INVENTION

[0003] The present invention is directed to power delivery, sensors and control systems, and more particularly directed to power delivery, sensors and control systems that operate in a wellbore environment to obtain and transmit data external of the wellbore.BACKGROUND OF THE INVENTION

[0004] Oil and gas and geothermal boreholes are often lined with steel casing. The steel casing is cemented in place by flowing cement between the casing and the subterranean formation. The space between the steel casing and the formation is referred to as the annulus. Intermittent monitoring of active wellbores is possible during production pauses using wireline tools deployed inside the casing but continuous monitoring of the environment or direct measurements in the cement or formation requires sensors outside the casing. Sensor installation outside the casing has historically been problematic due to the harsh subsurface environment and the need to avoid compromising the cement seal with long embedded wires. FIG. 1 illustrates a prior art downhole pipe that is used for traditional external cemented wiring applications.

[0005] The following is a general overview of a well completion:

[0006] A conductor casing is the largest diameter casing and is emplaced at or near the surface to be used as a guide for drilling a borehole approximately the size of the internal diameter of the conductor. The initial borehole is drilled deeper than conductor casing. After drilling to a depth determined by the drill team, a smaller diameter section of casing (the surface casing) is installed concentrically inside the conductor casing. When the surface casing is near the bottom of the drilled borehole, the drilling hardware is removed from the borehole and cement is flowed through the surface casing until it flows out of the annular space at the surface between the surface casing and the conductor casing. After the cement cures, the cement inside the surface casing is drilled out and the borehole drilling continues deeper past the surface casing into the formation. FIG. 1 illustrates a smart collar interface by wireline intervention according to an embodiment of the disclosure. This figure is not drawn to scale.

[0007] Next, a segment of intermediate casing is installed inside the surface casing in the same way described above. This narrowing of borehole size and concentrically installed smaller diameter casings is continued until the final segment of casing (the production casing) is installed. The space between the production casing and the surrounding rock formation is filled with cement for the permanent installation in the same way that the annulus between casing types is cemented. The steel casing is cemented in place by flowing cement between the smaller casing and larger concentric casing installations near the surface, and flowing cement between production casing and the subterranean formation in the deeper sections of the wellbore. The space between concentrically installed steel casing segments and / or the space between the production casing and the formation is referred to as the annulus.

[0008] Intermittent monitoring of active wellbores is possible during production pauses using wireline tools deployed inside the casing but continuous monitoring of the environment or direct measurements in the cement or formation requires sensors outside the casing. As discussed above, sensor installation outside the casing has historically been problematic due to the harsh subsurface environment and the need to avoid compromising the cement seal with long embedded wires. Emplacement and interface of sensors and control systems in the volume of the annulus of wellbore completions, the volume of cement packing, is of great interest to downhole industries and to the science community because it can provide important information about wellbore completions and the state of the surrounding formation.

[0009] Annular instrumentation is accomplished today in select applications by using transmission lines such as wires or fiber optic cables installed in the cement alongside the casing. These cement / cable run methods have been demonstrated as a rich source of wellbore information and have been implemented without introducing leaks. However, the added complexity of installation and the potential for leak paths developing along cables over time makes the implementation unattractive for many high-consequence applications. Additionally, cables can be damaged during installation and sensing at multiple depths often requires additional lines.

[0010] What is needed are systems and methods that enable applications such as long-term wellbore integrity sensing, seismic monitoring, flow detection, interface with sensors distributed in the cement, and valve control for production / injection from / into specified zones without introducing additional risk or installation complexity and that overcome the deficiencies and limitations of the prior art.SUMMARY OF THE INVENTION

[0011] The present disclosure is directed to systems and methods for data acquisition external to a casing in drilled wellbores. The systems include permanent data acquisition sensors and components mounted within and external to the well casing. The systems use smart collars and / or smart centralizers equipped with robust high-temperature electronics, and variations of acoustic / inductive / electrochemical / power harvest / wireline recharge technology. The smart collars and / or smart centralizers can replace and / or augment standard casing collars and centralizers. These systems are deployed during casing installation of new wells. These versatile data acquisition systems are capable of power, communication, and synchronization links installed outside wellbore casing without compromising wellbore integrity.

[0012] Establishment of a versatile downhole instrumentation system without transmission lines in the cement enable applications such as long-term wellbore integrity sensing, seismic monitoring, flow detection, interface with sensors distributed in the cement, and valve control for production / injection from / into specified zones. All these applications would be accomplished without introducing additional risk or installation complexity.

[0013] According to an embodiment of the disclosure, a monitoring system is disclosed that includes a power source; a power transmission system comprising a first transmission pathway within or adjacent to a wellbore casing; a communication system comprising a second transmission pathway within or adjacent to a wellbore casing; a casing collar or centralizer comprising a sensor connected to the communication and power transmission systems; and an instrumentation package.

[0014] According to another embodiment of the disclosure, a method of monitoring a downhole condition is disclosed that includes providing power to a downhole instrumentation; and communicating with a downhole sensor attached to or embedded in a casing collar, centralizer or wellbore casing to transmit condition data to a user above ground.

[0015] The described systems and approaches support the data acquisition system and sensor hardware deployed within and outside of the wellbore casing in subsurface boreholes. The data can be used for long-term wellbore integrity monitoring, event detection / characterization / localization, overall wellbore system health monitoring, and national security purposes.

[0016] An advantage of the present disclosure is to allow for permanent data acquisition installed external to the wellbore casing without compromising wellbore integrity or adding complexity to installation procedures.

[0017] Another advantage of the present disclosure is that the disclosed data acquisition systems and methods enable continuous monitoring of subsurface environments with various possible sensor types deployed in the cemented annulus.

[0018] Other features and advantages of the present invention will be apparent from the following more detailed description of the preferred embodiment, taken in conjunction with the accompanying drawings which illustrate, by way of example, the principles of the invention.BRIEF DESCRIPTION OF THE DRAWINGS

[0019] FIG. 1 illustrates a prior art downhole pipe that is used for traditional external cemented wiring applications.

[0020] FIG. 2 illustrates an acoustic power / communications smart collar, protective covering not shown, according to an embodiment of the disclosure.

[0021] FIG. 3 is a diagram of downhole instrumentation using concentric casing strings as power / communications conductors according to an embodiment of the disclosure. This figure is not drawn to scale.

[0022] FIG. 4 is a diagram of local power harvesting smart collar according to an embodiment of the disclosure. Communications are accomplished by other means.

[0023] FIG. 5 is a diagram of electrochemical technique according to an embodiment of the disclosure wherein a simple battery is constructed by use of metals separated on the electromotive series according to an embodiment of the disclosure. As shown, the smart collar housing (steel) acts as the cathode metal and the insert (aluminum, zinc, magnesium, etc.) acts as the reactive anode metal.

[0024] FIG. 6 is a diagram of smart collar interface by wireline intervention according to an embodiment of the disclosure. This figure is not drawn to scale.

[0025] FIG. 7 shows an acoustic power transmission test on steel drill pipe. Shown is the charge on a capacitor bank as received from a rectifier circuit attached to PZT stacks.

[0026] FIG. 8 shows wired pipe segments mounted on custom pipe stands and electronic interface test fixture with BNC connector output according to an embodiment of the disclosure.

[0027] FIG. 9 shows the results of S-Parameters for a single pipe segment (Segment A). Red marker (5.917 MHz) Green marker (15.801 MHz) Blue marker (24.915 MHz) according to an embodiment of the disclosure.

[0028] FIG. 10 shows the results of S-Parameters for a single pipe segment (Segment B). Red marker (6.029 MHz) Green marker (15.053 MHz) Blue marker (24.608 MHz) according to an embodiment of the disclosure.

[0029] FIG. 11 shows the results of S-Parameters for a single pipe segment (Segment C). Red marker (6.057 MHz) Green marker (14.941 MHz) Blue marker (24.310 MHz) according to an embodiment of the disclosure.

[0030] FIG. 12 shows the results of S-Parameters for a single pipe segment (Segment D). Red marker (6.169 MHz) Green marker (15.109 MHz) Blue marker (24.552 MHz) according to an embodiment of the disclosure.

[0031] FIG. 13 shows the results of S-Parameters for a single pipe segment (Segment E). Red marker (6.029 MHz) Green marker (14.718 MHz) Blue marker (24.245 MHz) according to an embodiment of the disclosure.

[0032] FIG. 14 shows the results of S-Parameters for two pipe segments (AB). Red marker (4.939 MHz) Green marker (7.370 MHz) Blue marker (16.254 MHz) according to an embodiment of the disclosure.

[0033] FIG. 15 shows the results of S-Parameters for three pipe segments (ABC). Red marker (4.325 MHz) Green marker (5.973 MHz) Blue marker (7.929 MHz) according to an embodiment of the disclosure.

[0034] FIG. 16 shows the results of S-Parameters for four pipe segments (ABCD). Red marker (5.191 MHz) Green marker (6.700 MHz) Blue marker (8.236 MHz) according to an embodiment of the disclosure.

[0035] FIG. 17 shows the results of S-Parameters for five pipe segments (ABCDE). Red marker (4.939 MHz) Green marker (5.973 MHz) Blue marker (7.342 MHz) according to an embodiment of the disclosure.

[0036] FIG. 18 is a photograph of a smart collar for interface with wired pipe according to an embodiment of the disclosure. Also shown are power management electronics and a sensor / control board.

[0037] FIG. 19 is a photograph of a wired pipe smart collar installed between wired pipe segments according to an embodiment of the disclosure. A multimeter was attached to measure charge on the capacitor bank during tests.DETAILED DESCRIPTION OF THE DISCLOSURE

[0038] The present disclosure is directed to systems and methods for data acquisition from outside a well casing. The systems and methods include a data acquisition system, a communications (comms) link and a power source. The data acquisition system includes a smart collar. The smart collar is capable of slowly charging capacitor banks to utilize in operations of querying sensors and transmitting data.

[0039] The power source may be a wired pipe system, an acoustic system, a concentric casing system, by power harvesting, an electrochemical power source and a wireline recharge system. The comms link may be via a wired pipe system, electromagnetic transmission, an acoustic transmission system, concentric casing, wireline retrieval are disclosed. These can be combined in hybrid approaches and configured as a multi-node repeater network depending on the requirements of a specific installation. In an embodiment, a data acquisition device near the bottom of an intermediate casing string can receive acoustic signals from deeper data acquisition systems and relay the signal to the surface electrically using a concentric casing system. All systems can be designed with wireline tool charging / data retrieval systems as a backup.

[0040] For implementations where power and communications are accomplished on the same modality (wired pipe, acoustic, concentric casing), frequency multiplexing can be used. Power is supplied from the surface at the most efficient transfer frequency and at the maximum safe operating amplitude. Data communications use the second most efficient frequency or band. For implementations where the power signal is not electrical (acoustic, local harvester), a set of transducers will be used to convert the signal to electrical power.

[0041] In most power modalities, the amount of power from the source may be too small to run the instrumentation directly and a power conditioning circuit will be required. The power conditioning circuit rectifies the power signal and steps the voltage up / down to an optimum energy storage voltage bank. Depending on the source and power demands, energy storage banks in or on the transmission pipe / casing may be charged over a period of hours or days or weeks. The energy storage bank will supply power to the control electronics and intended to provide short duration bursts of energy to accomplish the high-power needs of communication or valve switching.

[0042] In the simplest implementation, the communications approach will employ On-Off keying (OOK) to encode binary data. In OOK, the presence of a signal indicates a binary 1, and the non-presence indicates a binary 0 or vice-versa. More sophisticated bidirectional digital communication schemes will be possible in some installations (wired pipe, concentric casing). Sinusoidal modulation techniques such amplitude shift keying (ASK), phase shift keying (PSK), quadrature amplitude modulation (QAM), etc., will enable higher data transfer rates.

[0043] An embodiment of an operational sequence for systems with surface-based power sources is as follows. The surface system will provide a power signal for a designed duration to allow the capacitor banks to charge. After the start-up power duration is complete, the surface system will monitor for a “hello world” report data packet from the smart collar. The downhole microcontroller will execute a start-up routine and generate the hello world packet which contains system health diagnostics such as the energy storage bank voltage and collar temperature. Upon receipt of the hello world packet, the surface system will send an acknowledgement of the message along with instructions for the next transmission and then continue to provide the power signal for enough time to recharge the energy storage banks. The downhole microcontroller will interpret the instructions from the surface, execute the command when the energy storage bank is full, and transmit specified data to the surface.

[0044] In an embodiment, the electronics are all high-temperature electronics design including power conditioning, a data processing / control device (microcontroller, digital signal processor, field programmable gate array, etc.), digital memory, analog-to-digital converter, signal multiplexer, signal conditioning electronics for interfacing sensors, a low-power electronics energy storage bank, and a high-power electronics energy storage bank. High-temperature electronics components enable access to harsh subsurface environments and provide high-reliability in lower temperature regions. Specific instrumentation design requirements are driven by the phenomena to be observed. For example, applications with seismic sensors are likely to require high data rates and precise global time synchronization where implementations only monitoring temperature and pressure will not.

[0045] In an embodiment discussed in greater detail below, the hardware includes inductively coupled wired pipe, but most of the developments apply to any of the power / communications modalities discussed herein. Representative prototype electronics include a power conditioner, microcontroller, communications interface, a capacitor bank, and a few sensors. Frequency analysis and capacitor charge tests are performed on commercial wired pipe to determine an interface scheme. A functional prototype smart collar was constructed and tested using a wired pipe test station.

[0046] In an embodiment, a wired pipe is linked to inductive couplers to enable communications and power without creating a leak path. A smart collar can use an inductive couple from wired pipe to enable the communications and power to the instrumentation of the smart collar.

[0047] The present systems include high-temperature electronics to interface varied sensor types and to handle / control power, timing synchronization, and data link to the surface. High-temperature electronics components enable access to harsh subsurface environments and provide high-reliability in lower temperature regions. The system includes power handling electronics, a data processing / control device (microcontroller, digital signal processor, field programmable gate array, etc.), digital memory, analog to digital converter, signal multiplexer, and signal conditioning electronics for interfacing sensors. Specific design requirements are driven by the signals of interest to the phenomena to be observed. For example, applications with seismic sensors are likely to require high data rates and precise global time synchronization where implementations only monitoring temperature and pressure may not. The high-temperature data acquisition backbone system can be used to interface many types of wired sensors or wireless sensors embedded in the cement. Key challenges the described system embodiments address is power and communications techniques with the downhole instrumentation platform.

[0048] In other embodiments, the sensors can be used to monitor the cement casing, annulus casing, cement integrity and / or the formation surrounding the casing annulus. The sensors in the collar can then be used for monitoring signals such as seismic monitoring, gas and liquid concentration monitoring, wellbore integrity, pressure, temperature, or structural properties of the environment.

[0049] The subsurface instrumentation package can also be used to control downhole systems such as stimulation / production zone valves, temperature and seismic activity. With a surface-based interface for these embodiments, wellbore operators can monitor wellbore health remotely in real-time and perform control decisions.

[0050] In an embodiment, the system includes wired casing segments with inductive coupling at threaded joints connected to one or more smart collars. In an embodiment, the wired drill pipe is steel with an included wire embedded along the inside of the pipe wall. Inductive couplings at each pipe joint enable communication over long distances of pipe.

[0051] In another embodiment, the embedded wire casing technology and a custom collar with inductive coupling can be installed between the segments of wired casing pipe which enables long-term, real-time communication and power delivery to the subsurface sensing / control systems. The inductive couplings mandate a high-frequency alternating current power delivery, which has been demonstrated by the inventors. Future implementations of “wired” casing technology could be further developed to enable direct current power delivery and / or electrical contact between pipe segments or optical fiber contact feed-through between casing segments to be used for power / communication.

[0052] In another embodiment, electromagnetic (EM) (communication only) communication techniques are made through the host formation. In an embodiment, when EM communications can communicate to downhole drilling systems, they may be used in directional drilling operations. An onboard battery, a separate power delivery in the downhole system, and EM communications can be used individually or in combination. dDeep EM transmission drilling communication systems may be battery powered possible.

[0053] In another embodiment, acoustic waveforms may be transmitted along the steel casing to transmit data and power. Similar to other described embodiments, a small amount of acoustic energy can be collected over a long duration and then utilized over a short period to enable downhole electronics operation and communication to the surface.

[0054] In another embodiment, local downhole memory storage with periodic charging and data retrieval using a custom wireline tool may be used. Electrical contacts inside the casing wall can connect the sensor system external to the wellbore. Wireless charging would be possible through inductive coils in both the downhole system and the wireline charger.

[0055] In another embodiment, periodic wireline tool-based data retrieval and power bank recharge from the downhole sensors may be used.

[0056] In another embodiment the disclosed downhole systems may be locally powered by high-temperature energy storage super capacitor banks that can be charged by various power supplies. The capacitor banks can be charged slowly and then drained rapidly to meet the high energy power demands of EM or acoustic transmission, or system control, data collection in between transmissions is stored in local memory.

[0057] In an embodiment, energy bank capacitors may be used to power the smart couplings, the capacitors may be charged by multiple power supplies including:

[0058] 1. Wireline charging tool.

[0059] 2. Wired pipe AC power transmission (or DC if the direct contact pipe is developed, or power over fiber if fiber optic pipe linkage is developed).

[0060] 3. Power harvesting via thermoelectric generators powered by the temperature differential between the inside and outside of the casing.

[0061] 4. Power harvesting via piezoelectric generators or specialty dynamo systems powered by acoustic waves and / or vibration.

[0062] 5. Noninvasive flow mechanisms inside the wellbore. One embodiment can include using a permanent magnetic field to drive lateral ionic flow in passing wellbore fluids to develop a potential across electrodes.

[0063] 6. Specialty novel batteries placed inside the wellbore that can be replaced infrequently. In an embodiment, the specialty batteries can use the wellbore fluid as the electrolyte and simply be implemented by two dissimilar metals emplaced in the wellbore and electrically connected to the external sensing systems. One of the metals can be the casing itself so long as a more anodic metal is used as the sacrificial electrode. This approach has the additional benefit of protecting the casing from corrosion. Metal plates can be emplaced against the borehole wall to prevent disruption of flow.

[0064] 7. Power delivery using the concentric design of casing installation. Most wells consist of several steel casings emplaced concentrically with the casing getting smaller as the hole gets deeper. The annular space between the casing is filled with cement. Each casing in a concentric installation could possibly be used as an electrical conductor to transmit electrical energy or communications to downhole systems.

[0065] Regardless of the source of energy, the local electronics will require a power handling scheme. The energy bank capacitors require stable direct current voltage to act as long-term energy storage. The high-temperature power electronics will include rectification to convert transient and AC sources into DC, boost and / or buck converters to make the voltage usable for charging the capacitor energy storage bank and / or subsequently useable in the rest of the data acquisition unit, and solid-state switching.EXAMPLES1. Wired Pipe (Power and / or Communications)

[0066] Commercially available wired pipe carries wire inside the pipe wall with inductively coupled linkages between pipe segments (FIG. 1). This wiring configuration has been shown to operate as a reliable link between the surface and the subsurface during drilling operations. In an embodiment, a wired casing like a wired drill pipe can be used to create a reliable link to the subsurface without creating leak paths in the annulus nor disrupting the internal operations of the casing.

[0067] In an embodiment, the smart collar can act mechanically as a simple casing collar linking two segments of wired casing and be instrumented with electronics to receive power from and establish communications with the surface through the wired pipe. This creates a real-time data transmission link and on-demand power with no wires in the annulus.

[0068] Wired casing coupled with a smart downhole data acquisition unit is the “lowest hanging fruit” in the development of a reliable power / communications link without creating leak paths or adding installation complexity. However, wired casing will be much more expensive than standard casing.

[0069] Inductive couplings in the power / communications link mandate that any signals passed through multiple segments will be alternating current (AC). Complex impedance of long wire sections with multiple inductive couplings creates important and complex filter characteristics for the power / communications link. Characterization of the frequency performance of individual segments, inductive couplings, and multiple segments will be required to understand filter characteristics with respect to installation length (see later section). This evaluation provides critical information of the passband and frequency dependent characteristics of the link. The highest efficiency frequency (lowest attenuation) will be used for power transmission. Other frequencies in the passband are used for digital communication.

[0070] 2. Acoustics (Power and / or Communications) According to another embodiment, the production casing string is used as an acoustic waveguide to enable charging of a downhole energy storage bank using acoustic energy supplied from the surface. When a threshold of energy is reached in the energy bank, the system queries sensors and communicates data to the surface acoustically.

[0071] In prior work, acoustic data transmission over 12,000 feet of drill pipe has been demonstrated without repeaters. However, these systems were always powered with batteries. Achieving the appropriate level of acoustic power transmission to power a downhole smart collar system is a challenging and unproven approach but results obtained in this work (see later section) demonstrate its applicability. Like many low-power concepts, the power scheme is to convert acoustic energy to electrical energy over a long period of time and then use it quickly for high-power operations such as communication back to the surface (see FIG. 2).3. Concentric Casing Strings (Power and / or Communications)

[0072] Most wells consist of several steel casings emplaced concentrically with the casing getting smaller as the hole gets deeper. The annular space between the casing is filled with cement. In this embodiment, casing strings in a concentric installation are used as electrical conductors to transmit electrical energy to and accomplish communications with downhole systems. In an embodiment, downhole instrumentation systems can be installed as smart centralizers placed between the production casing and intermediate casing (see FIG. 3).4. Local Energy Harvesting (Power Only)

[0073] In this embodiment, energy is collected locally downhole from the surrounding environment (see FIG. 4). Downhole power harvesting can be implemented using many means which can be used individually or in combination.

[0074] Fluid flow inside the casing can be used as an energy source which is collected by traditional dynamo or by noninvasive means. In an embodiment, a noninvasive technique to harvest energy flow uses a permanent magnetic field to drive lateral ionic flow in passing wellbore fluids to develop a potential across fixed electrodes.

[0075] Thermoelectric generators can be used to harvest energy from the thermal gradient set up by fluids passing inside the casing that are warmer or colder than the annular space where the instrumentation is housed.

[0076] Vibrational energy from fluid flow or other downhole sources can be harvested.

[0077] As with acoustic power transmission, a small amount of power will be collected over a long period of time to charge energy storage banks.5. Replaceable Metallic Implants for Electrochemical Power (Power Only)

[0078] Specialty novel “batteries” can be created using two dissimilar metals inside the casing with wellbore fluid used as the electrolyte. These specialty batteries can be electrically connected to the external sensing systems. For simple implementations, the casing itself can be used as one of the metals. When using the casing as one metal, the second metal should be more anodic to act as the sacrificial battery electrode. The anodic metal would corrode over time and could be replaced by well intervention. This approach has the additional benefit of protecting the casing from corrosion. Anodic metal inserts can be emplaced against the borehole wall to prevent disruption of flow (see FIG. 5).6. Periodic Wireline Intervention (Power and / or Communications)

[0079] Wellbore smart systems can be powered and interfaced using periodic wireline tool intervention. The wireline tool is deployed in the wellbore and connects to each smart system from inside the casing (FIG. 6). Energy storage banks (capacitors or batteries) are charged by the wireline tool and data is retrieved from downhole nonvolatile memory. The systems can be designed to operate for long periods between interventions. Wireline interventions are typically avoided because they introduce risk and the wellbore is non-operational during the operation. However, this is a reliable possibility with few failure modes. Regardless of the power / communication modality selected, all implementations should be designed to accept this technique as a backup interface methodAcoustic Power Conceptual Feasibility Test

[0080] Stacks of lead zirconate titanate (PZT) piezoelectric material were fastened to a pin seat at the end of a ~1,400-foot horizontal string of 6-inch diameter steel drill pipe at Sandia. The PZT stacks were wired in parallel and attached to an EH300 energy harvest module. A digital multimeter was used to measure the charge on the EH300 capacitor as the drill pipe was struck with a sledgehammer at increasing distance along the drill pipe. As expected, the capacitor charges at a lower rate as the hammer is moved farther away. Hammer strikes at the maximum distance (~1,400 ft) from the PZT stacks still cause incremental increase of the capacitor charge voltage. At this distance, the hammer strikes could not be heard by ear through the air but could be heard clearly when standing near the pipe. FIG. 7 shows an acoustic power transmission test on steel drill pipe. Shown is the charge on a capacitor bank as received from a rectifier circuit attached to PZT stacks.Wired Pipe Frequency Analysis

[0081] Five wired pipe segments (Part: NWP0029-002, 5-inch diameter) were acquired from Intelliserv of National Oil Varco for these experiments. The pipe sections were laid out horizontally on custom pipe stands with steel ball v-shaped supports (FIG. 8). The steel balls allow axial and rotational freedom for experiments to enable sections to be moved apart or attached as needed. The pipes were labeled with unique letters A-E. Pipe was interfaced electronically using pin and box inductive coupling test fixtures Bayonet Neill-Concelman (BNC) output ports. Inductive coupling seats on the test fixtures and between each pipe segment were carefully wiped with a cloth before each connection to remove excess anti-seize. Frequency analysis data were collected using a NanoVNA Vector Network Analyzer (VNA).

[0082] VNA tests were performed on each pipe segment A-E individually (FIGS. 9-13) and then on joined sections AB (FIG. 14), ABC, (FIG. 15), ABCD (FIG. 16) and ABCDE (FIG. 17).

[0083] In these data, the “S11 Return Loss” parameter represents the power of the signal reflected back to the source within the wired pipe at each frequency. S11 is given as the reflected power relative to the source power. Lower S11 values means less signal is lost to internal reflection and is therefore taken as higher efficiency transfer. The “S21 Insertion Loss” parameter represents the power received at the distant end of the wired pipe assembly at each frequency. S21 is given as the power received at the distant end relative to the source power. Higher S21 values mean more power is received at the distant end and is therefore taken as higher efficiency transfer.

[0084] Optimum power transfer frequencies are selected by maximizing S21 Insertion Loss and minimizing S11 Return Loss. As S21 is the most direct measure of power transfer to the target, this parameter is given priority. Selected most effective frequencies from each pipe configuration are shown in Table 1.TABLE 1Tabulated highest efficiency frequencies for powertransfer. The marker colors Red, Green, and Bluerepresent the frequencies as marked in the plots.RedGreenBlue(MHz)(MHz)(MHz)Segment A5.91715.80124.915Segment B6.02915.05324.608Segment C6.05714.94124.310Segment D6.16915.10924.552Segment E6.02914.71824.245Segment AB4.9397.37016.254Segment ABC4.3255.9737.929Segment ABCD5.1916.7008.236Segment ABCDE4.9395.9737.342

[0085] Three approximate passbands are observable in all individual and joined segments, 4-8 MHz, 12-16 MHz, and 22-27 MHz. Little variance in frequency response was observed between individual segments of pipe. Addition of segments to the pipe chain adds peaks and valleys to the pass bands. In the first passband of the S21 Insertion Loss parameter plots, the number of peaks appears to correspond with the number of pipe segments in the test.Wired Pipe Usable Power Transfer Tests

[0086] In this experiment, usable power is defined as the rate of energy increase in a storage capacitor. An EH301 energy harvest module with a 6600 μF capacitor bank was attached to the BNC port of a wired pipe inductive couple test fixture. A waveform generator was attached to the BNC port of the test fixture at the other end of the tested wired pipe segment. The charge on the capacitor was monitored using various input signal settings. For each test, the capacitor was shorted until a confirmed stable 0V reading on the multimeter was achieved. The time to reach 1V was recorded and the approximate average power transfer rate was computed. Results from tests using a + / −5V sine wave are given in Table 2. Results from tests using a + / −10V sine wave are given in Table 3.TABLE 2+ / −5 V Sine wave energy transfer testscharging a 6600 μF capacitor bank.FrequencyTime to reachApproximate Received(MHz)1 V (s)Power (μW)A7.57245.8A65164.7B65560C65461.1D65560E65461.1AB57245.8AB66055AB7.59136.3ABC67146.5ABCD66253.2ABCD7.59534.7ABCDE5.827941.8ABCDE69734ABCDE7.516120.5TABLE 3+ / −10 V Sine wave energy transfer testscharging a 6600 μF capacitor bank.FrequencyTime to reachApproximate Received(MHz)1 V (s)Power (μW)A5.6917194.1A6.8822150AB5.0517194.1AB6.2820165AB7.4725132ABC4.6117194.1ABC5.7820165ABC6.6224137.5ABCD4.4019173.7ABCD5.2820165ABCD6.1924137.5ABCDE*4.2420165ABCDE4.9020165ABCDE5.7825132*An additional test was performed charging the capacitor bank to 5 V in this configuration. This test yielded a 249.2 μW average power transfer rate.Prototype Development and TestingFIG. 18 shows a smart collar according to an embodiment of the disclosure. The smart collar was and field tested using the horizontal wired pipe test station. Pipe is interfaced at either end of the prototype using the same type of pin and box inductive couplings that were used for the frequency performance analysis. The body of the prototype module was designed in Solidworks and constructed using 3-dimensional printed material. A removable protective covering was fixed to the body.

[0088] The electronics include an energy harvest module, a 5 F supercapacitor, an STM32F407 microcontroller with peripheral audio digital to analog converter (DAC) with a class D speaker driver, 3-axis accelerometer, and audio sensor. Electronics interface the inductive coils via BNC connectors. The design was intended to use the audio DAC with class D speaker driver as a convenient analog source for communications. The audio DAC was attractive because complex waveforms can be created to support more sophisticated communication techniques in future work such as QAM. Unfortunately, the prototype was developed before the wired pipe frequency response testing and the frequency bandwidth of the DAC is too low for effective communication in the wired pipe. A simple single transistor circuit driven by input / output microcontroller pin was later proven effective in the lab for OOK MHz transfer frequencies between inductive couplings.

[0089] The prototype was attached to segments of wired pipe (FIG. 19). The capacitor bank in the prototype was charged through the wired over a long period of time using a + / −10 V sinusoidal signal. The energy harvest circuit is designed to hold charge on the capacitor until it reaches 5 V and then to begin powering the circuitry until the capacitor voltage drops to approximately 3 V where it turns off again. The capacitor voltage increased as expected during these field tests. To fully charge the 5 F capacitor to 5 V over five pipe segments at the maximum measured power rate of ~250 μW would take approximately 67 hours. With this figure in mind, the capacitor was pre-charged to 4.8 V. The prototype was connected to the ABCDE pipe segment and after approximately 10 minutes, the capacitor reached 5 V, the microcontroller, sensors and peripheral electronics turned on and operated as expected for approximately 4 minutes before the power turned off and the capacitor began charging again.

[0090] While the invention has been described with reference to a preferred embodiment, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted for elements thereof without departing from the scope of the invention. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the invention without departing from the essential scope thereof. Therefore, it is intended that the invention not be limited to the particular embodiment disclosed as the best mode contemplated for carrying out this invention, but that the invention will include all embodiments falling within the scope of the appended claims.

Examples

examples

1. Wired Pipe (Power and / or Communications)

[0066]Commercially available wired pipe carries wire inside the pipe wall with inductively coupled linkages between pipe segments (FIG. 1). This wiring configuration has been shown to operate as a reliable link between the surface and the subsurface during drilling operations. In an embodiment, a wired casing like a wired drill pipe can be used to create a reliable link to the subsurface without creating leak paths in the annulus nor disrupting the internal operations of the casing.

[0067]In an embodiment, the smart collar can act mechanically as a simple casing collar linking two segments of wired casing and be instrumented with electronics to receive power from and establish communications with the surface through the wired pipe. This creates a real-time data transmission link and on-demand power with no wires in the annulus.

[0068]Wired casing coupled with a smart downhole data acquisition unit is the “lowest hanging fruit” in the developm...

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims priority to U.S. Provisional Application No. 63 / 748,231, filed on Jan. 22, 2025, entitled “Systems and Methods for Data Acquisition From Outside a Well Casing,” the entirety of which is incorporated herein by reference.GOVERNMENT INTEREST STATEMENT

[0002] This invention was made with Government support under Contract No. DE-NA0003525 awarded by the United States Department of Energy / National Nuclear Security Administration. The U.S. Government has certain rights in this invention.FIELD OF THE INVENTION

[0003] The present invention is directed to power delivery, sensors and control systems, and more particularly directed to power delivery, sensors and control systems that operate in a wellbore environment to obtain and transmit data external of the wellbore.BACKGROUND OF THE INVENTION

[0004] Oil and gas and geothermal boreholes are often lined with steel casing. The steel casing is cemented in place by flowing cement between the casing and the subterranean formation. The space between the steel casing and the formation is referred to as the annulus. Intermittent monitoring of active wellbores is possible during production pauses using wireline tools deployed inside the casing but continuous monitoring of the environment or direct measurements in the cement or formation requires sensors outside the casing. Sensor installation outside the casing has historically been problematic due to the harsh subsurface environment and the need to avoid compromising the cement seal with long embedded wires. FIG. 1 illustrates a prior art downhole pipe that is used for traditional external cemented wiring applications.

[0005] The following is a general overview of a well completion:

[0006] A conductor casing is the largest diameter casing and is emplaced at or near the surface to be used as a guide for drilling a borehole approximately the size of the internal diameter of the conductor. The initial borehole is drilled deeper than conductor casing. After drilling to a depth determined by the drill team, a smaller diameter section of casing (the surface casing) is installed concentrically inside the conductor casing. When the surface casing is near the bottom of the drilled borehole, the drilling hardware is removed from the borehole and cement is flowed through the surface casing until it flows out of the annular space at the surface between the surface casing and the conductor casing. After the cement cures, the cement inside the surface casing is drilled out and the borehole drilling continues deeper past the surface casing into the formation. FIG. 1 illustrates a smart collar interface by wireline intervention according to an embodiment of the disclosure. This figure is not drawn to scale.

[0007] Next, a segment of intermediate casing is installed inside the surface casing in the same way described above. This narrowing of borehole size and concentrically installed smaller diameter casings is continued until the final segment of casing (the production casing) is installed. The space between the production casing and the surrounding rock formation is filled with cement for the permanent installation in the same way that the annulus between casing types is cemented. The steel casing is cemented in place by flowing cement between the smaller casing and larger concentric casing installations near the surface, and flowing cement between production casing and the subterranean formation in the deeper sections of the wellbore. The space between concentrically installed steel casing segments and / or the space between the production casing and the formation is referred to as the annulus.

[0008] Intermittent monitoring of active wellbores is possible during production pauses using wireline tools deployed inside the casing but continuous monitoring of the environment or direct measurements in the cement or formation requires sensors outside the casing. As discussed above, sensor installation outside the casing has historically been problematic due to the harsh subsurface environment and the need to avoid compromising the cement seal with long embedded wires. Emplacement and interface of sensors and control systems in the volume of the annulus of wellbore completions, the volume of cement packing, is of great interest to downhole industries and to the science community because it can provide important information about wellbore completions and the state of the surrounding formation.

[0009] Annular instrumentation is accomplished today in select applications by using transmission lines such as wires or fiber optic cables installed in the cement alongside the casing. These cement / cable run methods have been demonstrated as a rich source of wellbore information and have been implemented without introducing leaks. However, the added complexity of installation and the potential for leak paths developing along cables over time makes the implementation unattractive for many high-consequence applications. Additionally, cables can be damaged during installation and sensing at multiple depths often requires additional lines.

[0010] What is needed are systems and methods that enable applications such as long-term wellbore integrity sensing, seismic monitoring, flow detection, interface with sensors distributed in the cement, and valve control for production / injection from / into specified zones without introducing additional risk or installation complexity and that overcome the deficiencies and limitations of the prior art.SUMMARY OF THE INVENTION

[0011] The present disclosure is directed to systems and methods for data acquisition external to a casing in drilled wellbores. The systems include permanent data acquisition sensors and components mounted within and external to the well casing. The systems use smart collars and / or smart centralizers equipped with robust high-temperature electronics, and variations of acoustic / inductive / electrochemical / power harvest / wireline recharge technology. The smart collars and / or smart centralizers can replace and / or augment standard casing collars and centralizers. These systems are deployed during casing installation of new wells. These versatile data acquisition systems are capable of power, communication, and synchronization links installed outside wellbore casing without compromising wellbore integrity.

[0012] Establishment of a versatile downhole instrumentation system without transmission lines in the cement enable applications such as long-term wellbore integrity sensing, seismic monitoring, flow detection, interface with sensors distributed in the cement, and valve control for production / injection from / into specified zones. All these applications would be accomplished without introducing additional risk or installation complexity.

[0013] According to an embodiment of the disclosure, a monitoring system is disclosed that includes a power source; a power transmission system comprising a first transmission pathway within or adjacent to a wellbore casing; a communication system comprising a second transmission pathway within or adjacent to a wellbore casing; a casing collar or centralizer comprising a sensor connected to the communication and power transmission systems; and an instrumentation package.

[0014] According to another embodiment of the disclosure, a method of monitoring a downhole condition is disclosed that includes providing power to a downhole instrumentation; and communicating with a downhole sensor attached to or embedded in a casing collar, centralizer or wellbore casing to transmit condition data to a user above ground.

[0015] The described systems and approaches support the data acquisition system and sensor hardware deployed within and outside of the wellbore casing in subsurface boreholes. The data can be used for long-term wellbore integrity monitoring, event detection / characterization / localization, overall wellbore system health monitoring, and national security purposes.

[0016] An advantage of the present disclosure is to allow for permanent data acquisition installed external to the wellbore casing without compromising wellbore integrity or adding complexity to installation procedures.

[0017] Another advantage of the present disclosure is that the disclosed data acquisition systems and methods enable continuous monitoring of subsurface environments with various possible sensor types deployed in the cemented annulus.

[0018] Other features and advantages of the present invention will be apparent from the following more detailed description of the preferred embodiment, taken in conjunction with the accompanying drawings which illustrate, by way of example, the principles of the invention.BRIEF DESCRIPTION OF THE DRAWINGS

[0019] FIG. 1 illustrates a prior art downhole pipe that is used for traditional external cemented wiring applications.

[0020] FIG. 2 illustrates an acoustic power / communications smart collar, protective covering not shown, according to an embodiment of the disclosure.

[0021] FIG. 3 is a diagram of downhole instrumentation using concentric casing strings as power / communications conductors according to an embodiment of the disclosure. This figure is not drawn to scale.

[0022] FIG. 4 is a diagram of local power harvesting smart collar according to an embodiment of the disclosure. Communications are accomplished by other means.

[0023] FIG. 5 is a diagram of electrochemical technique according to an embodiment of the disclosure wherein a simple battery is constructed by use of metals separated on the electromotive series according to an embodiment of the disclosure. As shown, the smart collar housing (steel) acts as the cathode metal and the insert (aluminum, zinc, magnesium, etc.) acts as the reactive anode metal.

[0024] FIG. 6 is a diagram of smart collar interface by wireline intervention according to an embodiment of the disclosure. This figure is not drawn to scale.

[0025] FIG. 7 shows an acoustic power transmission test on steel drill pipe. Shown is the charge on a capacitor bank as received from a rectifier circuit attached to PZT stacks.

[0026] FIG. 8 shows wired pipe segments mounted on custom pipe stands and electronic interface test fixture with BNC connector output according to an embodiment of the disclosure.

[0027] FIG. 9 shows the results of S-Parameters for a single pipe segment (Segment A). Red marker (5.917 MHz) Green marker (15.801 MHz) Blue marker (24.915 MHz) according to an embodiment of the disclosure.

[0028] FIG. 10 shows the results of S-Parameters for a single pipe segment (Segment B). Red marker (6.029 MHz) Green marker (15.053 MHz) Blue marker (24.608 MHz) according to an embodiment of the disclosure.

[0029] FIG. 11 shows the results of S-Parameters for a single pipe segment (Segment C). Red marker (6.057 MHz) Green marker (14.941 MHz) Blue marker (24.310 MHz) according to an embodiment of the disclosure.

[0030] FIG. 12 shows the results of S-Parameters for a single pipe segment (Segment D). Red marker (6.169 MHz) Green marker (15.109 MHz) Blue marker (24.552 MHz) according to an embodiment of the disclosure.

[0031] FIG. 13 shows the results of S-Parameters for a single pipe segment (Segment E). Red marker (6.029 MHz) Green marker (14.718 MHz) Blue marker (24.245 MHz) according to an embodiment of the disclosure.

[0032] FIG. 14 shows the results of S-Parameters for two pipe segments (AB). Red marker (4.939 MHz) Green marker (7.370 MHz) Blue marker (16.254 MHz) according to an embodiment of the disclosure.

[0033] FIG. 15 shows the results of S-Parameters for three pipe segments (ABC). Red marker (4.325 MHz) Green marker (5.973 MHz) Blue marker (7.929 MHz) according to an embodiment of the disclosure.

[0034] FIG. 16 shows the results of S-Parameters for four pipe segments (ABCD). Red marker (5.191 MHz) Green marker (6.700 MHz) Blue marker (8.236 MHz) according to an embodiment of the disclosure.

[0035] FIG. 17 shows the results of S-Parameters for five pipe segments (ABCDE). Red marker (4.939 MHz) Green marker (5.973 MHz) Blue marker (7.342 MHz) according to an embodiment of the disclosure.

[0036] FIG. 18 is a photograph of a smart collar for interface with wired pipe according to an embodiment of the disclosure. Also shown are power management electronics and a sensor / control board.

[0037] FIG. 19 is a photograph of a wired pipe smart collar installed between wired pipe segments according to an embodiment of the disclosure. A multimeter was attached to measure charge on the capacitor bank during tests.DETAILED DESCRIPTION OF THE DISCLOSURE

[0038] The present disclosure is directed to systems and methods for data acquisition from outside a well casing. The systems and methods include a data acquisition system, a communications (comms) link and a power source. The data acquisition system includes a smart collar. The smart collar is capable of slowly charging capacitor banks to utilize in operations of querying sensors and transmitting data.

[0039] The power source may be a wired pipe system, an acoustic system, a concentric casing system, by power harvesting, an electrochemical power source and a wireline recharge system. The comms link may be via a wired pipe system, electromagnetic transmission, an acoustic transmission system, concentric casing, wireline retrieval are disclosed. These can be combined in hybrid approaches and configured as a multi-node repeater network depending on the requirements of a specific installation. In an embodiment, a data acquisition device near the bottom of an intermediate casing string can receive acoustic signals from deeper data acquisition systems and relay the signal to the surface electrically using a concentric casing system. All systems can be designed with wireline tool charging / data retrieval systems as a backup.

[0040] For implementations where power and communications are accomplished on the same modality (wired pipe, acoustic, concentric casing), frequency multiplexing can be used. Power is supplied from the surface at the most efficient transfer frequency and at the maximum safe operating amplitude. Data communications use the second most efficient frequency or band. For implementations where the power signal is not electrical (acoustic, local harvester), a set of transducers will be used to convert the signal to electrical power.

[0041] In most power modalities, the amount of power from the source may be too small to run the instrumentation directly and a power conditioning circuit will be required. The power conditioning circuit rectifies the power signal and steps the voltage up / down to an optimum energy storage voltage bank. Depending on the source and power demands, energy storage banks in or on the transmission pipe / casing may be charged over a period of hours or days or weeks. The energy storage bank will supply power to the control electronics and intended to provide short duration bursts of energy to accomplish the high-power needs of communication or valve switching.

[0042] In the simplest implementation, the communications approach will employ On-Off keying (OOK) to encode binary data. In OOK, the presence of a signal indicates a binary 1, and the non-presence indicates a binary 0 or vice-versa. More sophisticated bidirectional digital communication schemes will be possible in some installations (wired pipe, concentric casing). Sinusoidal modulation techniques such amplitude shift keying (ASK), phase shift keying (PSK), quadrature amplitude modulation (QAM), etc., will enable higher data transfer rates.

[0043] An embodiment of an operational sequence for systems with surface-based power sources is as follows. The surface system will provide a power signal for a designed duration to allow the capacitor banks to charge. After the start-up power duration is complete, the surface system will monitor for a “hello world” report data packet from the smart collar. The downhole microcontroller will execute a start-up routine and generate the hello world packet which contains system health diagnostics such as the energy storage bank voltage and collar temperature. Upon receipt of the hello world packet, the surface system will send an acknowledgement of the message along with instructions for the next transmission and then continue to provide the power signal for enough time to recharge the energy storage banks. The downhole microcontroller will interpret the instructions from the surface, execute the command when the energy storage bank is full, and transmit specified data to the surface.

[0044] In an embodiment, the electronics are all high-temperature electronics design including power conditioning, a data processing / control device (microcontroller, digital signal processor, field programmable gate array, etc.), digital memory, analog-to-digital converter, signal multiplexer, signal conditioning electronics for interfacing sensors, a low-power electronics energy storage bank, and a high-power electronics energy storage bank. High-temperature electronics components enable access to harsh subsurface environments and provide high-reliability in lower temperature regions. Specific instrumentation design requirements are driven by the phenomena to be observed. For example, applications with seismic sensors are likely to require high data rates and precise global time synchronization where implementations only monitoring temperature and pressure will not.

[0045] In an embodiment discussed in greater detail below, the hardware includes inductively coupled wired pipe, but most of the developments apply to any of the power / communications modalities discussed herein. Representative prototype electronics include a power conditioner, microcontroller, communications interface, a capacitor bank, and a few sensors. Frequency analysis and capacitor charge tests are performed on commercial wired pipe to determine an interface scheme. A functional prototype smart collar was constructed and tested using a wired pipe test station.

[0046] In an embodiment, a wired pipe is linked to inductive couplers to enable communications and power without creating a leak path. A smart collar can use an inductive couple from wired pipe to enable the communications and power to the instrumentation of the smart collar.

[0047] The present systems include high-temperature electronics to interface varied sensor types and to handle / control power, timing synchronization, and data link to the surface. High-temperature electronics components enable access to harsh subsurface environments and provide high-reliability in lower temperature regions. The system includes power handling electronics, a data processing / control device (microcontroller, digital signal processor, field programmable gate array, etc.), digital memory, analog to digital converter, signal multiplexer, and signal conditioning electronics for interfacing sensors. Specific design requirements are driven by the signals of interest to the phenomena to be observed. For example, applications with seismic sensors are likely to require high data rates and precise global time synchronization where implementations only monitoring temperature and pressure may not. The high-temperature data acquisition backbone system can be used to interface many types of wired sensors or wireless sensors embedded in the cement. Key challenges the described system embodiments address is power and communications techniques with the downhole instrumentation platform.

[0048] In other embodiments, the sensors can be used to monitor the cement casing, annulus casing, cement integrity and / or the formation surrounding the casing annulus. The sensors in the collar can then be used for monitoring signals such as seismic monitoring, gas and liquid concentration monitoring, wellbore integrity, pressure, temperature, or structural properties of the environment.

[0049] The subsurface instrumentation package can also be used to control downhole systems such as stimulation / production zone valves, temperature and seismic activity. With a surface-based interface for these embodiments, wellbore operators can monitor wellbore health remotely in real-time and perform control decisions.

[0050] In an embodiment, the system includes wired casing segments with inductive coupling at threaded joints connected to one or more smart collars. In an embodiment, the wired drill pipe is steel with an included wire embedded along the inside of the pipe wall. Inductive couplings at each pipe joint enable communication over long distances of pipe.

[0051] In another embodiment, the embedded wire casing technology and a custom collar with inductive coupling can be installed between the segments of wired casing pipe which enables long-term, real-time communication and power delivery to the subsurface sensing / control systems. The inductive couplings mandate a high-frequency alternating current power delivery, which has been demonstrated by the inventors. Future implementations of “wired” casing technology could be further developed to enable direct current power delivery and / or electrical contact between pipe segments or optical fiber contact feed-through between casing segments to be used for power / communication.

[0052] In another embodiment, electromagnetic (EM) (communication only) communication techniques are made through the host formation. In an embodiment, when EM communications can communicate to downhole drilling systems, they may be used in directional drilling operations. An onboard battery, a separate power delivery in the downhole system, and EM communications can be used individually or in combination. dDeep EM transmission drilling communication systems may be battery powered possible.

[0053] In another embodiment, acoustic waveforms may be transmitted along the steel casing to transmit data and power. Similar to other described embodiments, a small amount of acoustic energy can be collected over a long duration and then utilized over a short period to enable downhole electronics operation and communication to the surface.

[0054] In another embodiment, local downhole memory storage with periodic charging and data retrieval using a custom wireline tool may be used. Electrical contacts inside the casing wall can connect the sensor system external to the wellbore. Wireless charging would be possible through inductive coils in both the downhole system and the wireline charger.

[0055] In another embodiment, periodic wireline tool-based data retrieval and power bank recharge from the downhole sensors may be used.

[0056] In another embodiment the disclosed downhole systems may be locally powered by high-temperature energy storage super capacitor banks that can be charged by various power supplies. The capacitor banks can be charged slowly and then drained rapidly to meet the high energy power demands of EM or acoustic transmission, or system control, data collection in between transmissions is stored in local memory.

[0057] In an embodiment, energy bank capacitors may be used to power the smart couplings, the capacitors may be charged by multiple power supplies including:

[0058] 1. Wireline charging tool.

[0059] 2. Wired pipe AC power transmission (or DC if the direct contact pipe is developed, or power over fiber if fiber optic pipe linkage is developed).

[0060] 3. Power harvesting via thermoelectric generators powered by the temperature differential between the inside and outside of the casing.

[0061] 4. Power harvesting via piezoelectric generators or specialty dynamo systems powered by acoustic waves and / or vibration.

[0062] 5. Noninvasive flow mechanisms inside the wellbore. One embodiment can include using a permanent magnetic field to drive lateral ionic flow in passing wellbore fluids to develop a potential across electrodes.

[0063] 6. Specialty novel batteries placed inside the wellbore that can be replaced infrequently. In an embodiment, the specialty batteries can use the wellbore fluid as the electrolyte and simply be implemented by two dissimilar metals emplaced in the wellbore and electrically connected to the external sensing systems. One of the metals can be the casing itself so long as a more anodic metal is used as the sacrificial electrode. This approach has the additional benefit of protecting the casing from corrosion. Metal plates can be emplaced against the borehole wall to prevent disruption of flow.

[0064] 7. Power delivery using the concentric design of casing installation. Most wells consist of several steel casings emplaced concentrically with the casing getting smaller as the hole gets deeper. The annular space between the casing is filled with cement. Each casing in a concentric installation could possibly be used as an electrical conductor to transmit electrical energy or communications to downhole systems.

[0065] Regardless of the source of energy, the local electronics will require a power handling scheme. The energy bank capacitors require stable direct current voltage to act as long-term energy storage. The high-temperature power electronics will include rectification to convert transient and AC sources into DC, boost and / or buck converters to make the voltage usable for charging the capacitor energy storage bank and / or subsequently useable in the rest of the data acquisition unit, and solid-state switching.EXAMPLES1. Wired Pipe (Power and / or Communications)

[0066] Commercially available wired pipe carries wire inside the pipe wall with inductively coupled linkages between pipe segments (FIG. 1). This wiring configuration has been shown to operate as a reliable link between the surface and the subsurface during drilling operations. In an embodiment, a wired casing like a wired drill pipe can be used to create a reliable link to the subsurface without creating leak paths in the annulus nor disrupting the internal operations of the casing.

[0067] In an embodiment, the smart collar can act mechanically as a simple casing collar linking two segments of wired casing and be instrumented with electronics to receive power from and establish communications with the surface through the wired pipe. This creates a real-time data transmission link and on-demand power with no wires in the annulus.

[0068] Wired casing coupled with a smart downhole data acquisition unit is the “lowest hanging fruit” in the development of a reliable power / communications link without creating leak paths or adding installation complexity. However, wired casing will be much more expensive than standard casing.

[0069] Inductive couplings in the power / communications link mandate that any signals passed through multiple segments will be alternating current (AC). Complex impedance of long wire sections with multiple inductive couplings creates important and complex filter characteristics for the power / communications link. Characterization of the frequency performance of individual segments, inductive couplings, and multiple segments will be required to understand filter characteristics with respect to installation length (see later section). This evaluation provides critical information of the passband and frequency dependent characteristics of the link. The highest efficiency frequency (lowest attenuation) will be used for power transmission. Other frequencies in the passband are used for digital communication.

[0070] 2. Acoustics (Power and / or Communications) According to another embodiment, the production casing string is used as an acoustic waveguide to enable charging of a downhole energy storage bank using acoustic energy supplied from the surface. When a threshold of energy is reached in the energy bank, the system queries sensors and communicates data to the surface acoustically.

[0071] In prior work, acoustic data transmission over 12,000 feet of drill pipe has been demonstrated without repeaters. However, these systems were always powered with batteries. Achieving the appropriate level of acoustic power transmission to power a downhole smart collar system is a challenging and unproven approach but results obtained in this work (see later section) demonstrate its applicability. Like many low-power concepts, the power scheme is to convert acoustic energy to electrical energy over a long period of time and then use it quickly for high-power operations such as communication back to the surface (see FIG. 2).3. Concentric Casing Strings (Power and / or Communications)

[0072] Most wells consist of several steel casings emplaced concentrically with the casing getting smaller as the hole gets deeper. The annular space between the casing is filled with cement. In this embodiment, casing strings in a concentric installation are used as electrical conductors to transmit electrical energy to and accomplish communications with downhole systems. In an embodiment, downhole instrumentation systems can be installed as smart centralizers placed between the production casing and intermediate casing (see FIG. 3).4. Local Energy Harvesting (Power Only)

[0073] In this embodiment, energy is collected locally downhole from the surrounding environment (see FIG. 4). Downhole power harvesting can be implemented using many means which can be used individually or in combination.

[0074] Fluid flow inside the casing can be used as an energy source which is collected by traditional dynamo or by noninvasive means. In an embodiment, a noninvasive technique to harvest energy flow uses a permanent magnetic field to drive lateral ionic flow in passing wellbore fluids to develop a potential across fixed electrodes.

[0075] Thermoelectric generators can be used to harvest energy from the thermal gradient set up by fluids passing inside the casing that are warmer or colder than the annular space where the instrumentation is housed.

[0076] Vibrational energy from fluid flow or other downhole sources can be harvested.

[0077] As with acoustic power transmission, a small amount of power will be collected over a long period of time to charge energy storage banks.5. Replaceable Metallic Implants for Electrochemical Power (Power Only)

[0078] Specialty novel “batteries” can be created using two dissimilar metals inside the casing with wellbore fluid used as the electrolyte. These specialty batteries can be electrically connected to the external sensing systems. For simple implementations, the casing itself can be used as one of the metals. When using the casing as one metal, the second metal should be more anodic to act as the sacrificial battery electrode. The anodic metal would corrode over time and could be replaced by well intervention. This approach has the additional benefit of protecting the casing from corrosion. Anodic metal inserts can be emplaced against the borehole wall to prevent disruption of flow (see FIG. 5).6. Periodic Wireline Intervention (Power and / or Communications)

[0079] Wellbore smart systems can be powered and interfaced using periodic wireline tool intervention. The wireline tool is deployed in the wellbore and connects to each smart system from inside the casing (FIG. 6). Energy storage banks (capacitors or batteries) are charged by the wireline tool and data is retrieved from downhole nonvolatile memory. The systems can be designed to operate for long periods between interventions. Wireline interventions are typically avoided because they introduce risk and the wellbore is non-operational during the operation. However, this is a reliable possibility with few failure modes. Regardless of the power / communication modality selected, all implementations should be designed to accept this technique as a backup interface methodAcoustic Power Conceptual Feasibility Test

[0080] Stacks of lead zirconate titanate (PZT) piezoelectric material were fastened to a pin seat at the end of a ~1,400-foot horizontal string of 6-inch diameter steel drill pipe at Sandia. The PZT stacks were wired in parallel and attached to an EH300 energy harvest module. A digital multimeter was used to measure the charge on the EH300 capacitor as the drill pipe was struck with a sledgehammer at increasing distance along the drill pipe. As expected, the capacitor charges at a lower rate as the hammer is moved farther away. Hammer strikes at the maximum distance (~1,400 ft) from the PZT stacks still cause incremental increase of the capacitor charge voltage. At this distance, the hammer strikes could not be heard by ear through the air but could be heard clearly when standing near the pipe. FIG. 7 shows an acoustic power transmission test on steel drill pipe. Shown is the charge on a capacitor bank as received from a rectifier circuit attached to PZT stacks.Wired Pipe Frequency Analysis

[0081] Five wired pipe segments (Part: NWP0029-002, 5-inch diameter) were acquired from Intelliserv of National Oil Varco for these experiments. The pipe sections were laid out horizontally on custom pipe stands with steel ball v-shaped supports (FIG. 8). The steel balls allow axial and rotational freedom for experiments to enable sections to be moved apart or attached as needed. The pipes were labeled with unique letters A-E. Pipe was interfaced electronically using pin and box inductive coupling test fixtures Bayonet Neill-Concelman (BNC) output ports. Inductive coupling seats on the test fixtures and between each pipe segment were carefully wiped with a cloth before each connection to remove excess anti-seize. Frequency analysis data were collected using a NanoVNA Vector Network Analyzer (VNA).

[0082] VNA tests were performed on each pipe segment A-E individually (FIGS. 9-13) and then on joined sections AB (FIG. 14), ABC, (FIG. 15), ABCD (FIG. 16) and ABCDE (FIG. 17).

[0083] In these data, the “S11 Return Loss” parameter represents the power of the signal reflected back to the source within the wired pipe at each frequency. S11 is given as the reflected power relative to the source power. Lower S11 values means less signal is lost to internal reflection and is therefore taken as higher efficiency transfer. The “S21 Insertion Loss” parameter represents the power received at the distant end of the wired pipe assembly at each frequency. S21 is given as the power received at the distant end relative to the source power. Higher S21 values mean more power is received at the distant end and is therefore taken as higher efficiency transfer.

[0084] Optimum power transfer frequencies are selected by maximizing S21 Insertion Loss and minimizing S11 Return Loss. As S21 is the most direct measure of power transfer to the target, this parameter is given priority. Selected most effective frequencies from each pipe configuration are shown in Table 1.TABLE 1Tabulated highest efficiency frequencies for powertransfer. The marker colors Red, Green, and Bluerepresent the frequencies as marked in the plots.RedGreenBlue(MHz)(MHz)(MHz)Segment A5.91715.80124.915Segment B6.02915.05324.608Segment C6.05714.94124.310Segment D6.16915.10924.552Segment E6.02914.71824.245Segment AB4.9397.37016.254Segment ABC4.3255.9737.929Segment ABCD5.1916.7008.236Segment ABCDE4.9395.9737.342

[0085] Three approximate passbands are observable in all individual and joined segments, 4-8 MHz, 12-16 MHz, and 22-27 MHz. Little variance in frequency response was observed between individual segments of pipe. Addition of segments to the pipe chain adds peaks and valleys to the pass bands. In the first passband of the S21 Insertion Loss parameter plots, the number of peaks appears to correspond with the number of pipe segments in the test.Wired Pipe Usable Power Transfer Tests

[0086] In this experiment, usable power is defined as the rate of energy increase in a storage capacitor. An EH301 energy harvest module with a 6600 μF capacitor bank was attached to the BNC port of a wired pipe inductive couple test fixture. A waveform generator was attached to the BNC port of the test fixture at the other end of the tested wired pipe segment. The charge on the capacitor was monitored using various input signal settings. For each test, the capacitor was shorted until a confirmed stable 0V reading on the multimeter was achieved. The time to reach 1V was recorded and the approximate average power transfer rate was computed. Results from tests using a + / −5V sine wave are given in Table 2. Results from tests using a + / −10V sine wave are given in Table 3.TABLE 2+ / −5 V Sine wave energy transfer testscharging a 6600 μF capacitor bank.FrequencyTime to reachApproximate Received(MHz)1 V (s)Power (μW)A7.57245.8A65164.7B65560C65461.1D65560E65461.1AB57245.8AB66055AB7.59136.3ABC67146.5ABCD66253.2ABCD7.59534.7ABCDE5.827941.8ABCDE69734ABCDE7.516120.5TABLE 3+ / −10 V Sine wave energy transfer testscharging a 6600 μF capacitor bank.FrequencyTime to reachApproximate Received(MHz)1 V (s)Power (μW)A5.6917194.1A6.8822150AB5.0517194.1AB6.2820165AB7.4725132ABC4.6117194.1ABC5.7820165ABC6.6224137.5ABCD4.4019173.7ABCD5.2820165ABCD6.1924137.5ABCDE*4.2420165ABCDE4.9020165ABCDE5.7825132*An additional test was performed charging the capacitor bank to 5 V in this configuration. This test yielded a 249.2 μW average power transfer rate.Prototype Development and TestingFIG. 18 shows a smart collar according to an embodiment of the disclosure. The smart collar was and field tested using the horizontal wired pipe test station. Pipe is interfaced at either end of the prototype using the same type of pin and box inductive couplings that were used for the frequency performance analysis. The body of the prototype module was designed in Solidworks and constructed using 3-dimensional printed material. A removable protective covering was fixed to the body.

[0088] The electronics include an energy harvest module, a 5 F supercapacitor, an STM32F407 microcontroller with peripheral audio digital to analog converter (DAC) with a class D speaker driver, 3-axis accelerometer, and audio sensor. Electronics interface the inductive coils via BNC connectors. The design was intended to use the audio DAC with class D speaker driver as a convenient analog source for communications. The audio DAC was attractive because complex waveforms can be created to support more sophisticated communication techniques in future work such as QAM. Unfortunately, the prototype was developed before the wired pipe frequency response testing and the frequency bandwidth of the DAC is too low for effective communication in the wired pipe. A simple single transistor circuit driven by input / output microcontroller pin was later proven effective in the lab for OOK MHz transfer frequencies between inductive couplings.

[0089] The prototype was attached to segments of wired pipe (FIG. 19). The capacitor bank in the prototype was charged through the wired over a long period of time using a + / −10 V sinusoidal signal. The energy harvest circuit is designed to hold charge on the capacitor until it reaches 5 V and then to begin powering the circuitry until the capacitor voltage drops to approximately 3 V where it turns off again. The capacitor voltage increased as expected during these field tests. To fully charge the 5 F capacitor to 5 V over five pipe segments at the maximum measured power rate of ~250 μW would take approximately 67 hours. With this figure in mind, the capacitor was pre-charged to 4.8 V. The prototype was connected to the ABCDE pipe segment and after approximately 10 minutes, the capacitor reached 5 V, the microcontroller, sensors and peripheral electronics turned on and operated as expected for approximately 4 minutes before the power turned off and the capacitor began charging again.

[0090] While the invention has been described with reference to a preferred embodiment, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted for elements thereof without departing from the scope of the invention. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the invention without departing from the essential scope thereof. Therefore, it is intended that the invention not be limited to the particular embodiment disclosed as the best mode contemplated for carrying out this invention, but that the invention will include all embodiments falling within the scope of the appended claims.

Examples

examples

1. Wired Pipe (Power and / or Communications)

[0066]Commercially available wired pipe carries wire inside the pipe wall with inductively coupled linkages between pipe segments (FIG. 1). This wiring configuration has been shown to operate as a reliable link between the surface and the subsurface during drilling operations. In an embodiment, a wired casing like a wired drill pipe can be used to create a reliable link to the subsurface without creating leak paths in the annulus nor disrupting the internal operations of the casing.

[0067]In an embodiment, the smart collar can act mechanically as a simple casing collar linking two segments of wired casing and be instrumented with electronics to receive power from and establish communications with the surface through the wired pipe. This creates a real-time data transmission link and on-demand power with no wires in the annulus.

[0068]Wired casing coupled with a smart downhole data acquisition unit is the “lowest hanging fruit” in the developm...

Claims

1. A monitoring system, comprising:a power source;a power transmission system comprising a first transmission pathway within or adjacent to a wellbore casing;a communication system comprising a second transmission pathway within or adjacent to a wellbore casing;a casing collar or centralizer comprising a sensor connected to the communication and power transmission systems; andan instrumentation package.

2. The system of claim 1, wherein the first and second transmission pathways are the same.

3. The system of claim 1, wherein the collar or centralizer further comprises a rechargeable energy source.

4. The system of claim 1, wherein the wellbore casing comprises a rechargeable energy source.

5. The system of claim 1, wherein the power source and power transmission system is selected from a group consisting of:a wired pipe: An AC signal generated from the surface propagates to the instrumentation where the energy is harvested and stored locally until enough energy is stored for the instrumentations electronic operation;concentric casing: The Intermediate Casing and Production casing is used as the conductor to transmit a DC or AC signal to the Smart Centralizer instrumentation; andan energy harvester.

6. The system of claim 5, wherein the wherein the wired pipe is configured to propagate an AC signal generated from an area at or near the surface to the instrumentation package where energy is harvested and stored locally until enough energy is stored for operation of the instrumentation package.

7. The system 5, wherein the power transmission system is a concentric casing and is a conduction that transmits a DC or AC signal to the Smart Centralizer instrumentation.

8. The system of claim 5, wherein the power system is an energy harvester.

9. The system of claim 1, wherein the energy harvester may comprise one or more energy harvesters selected from a group comprising a permanent magnetic field, a thermoelectric generator, a vibrational energy harvester, an acoustic energy harvester, an electrode metal insert power source, and a wireline.

10. The system of claim 9, wherein the permanent magnet field drives lateral ionic flow in passing wellbore fluids to develop a potential across fixed electrodes.

11. The system of claim 9, wherein the thermoelectric generator harvests energy via the thermal gradient between surrounding rock temperature and fluid flowing through the pipe.

12. The system of claim 9, wherein the acoustic energy harvester harvests energy from an acoustic signal propagated from the surface and stores the energy in an energy storage device.

13. The system of claim 1, wherein the communication system is selected from a group consisting of a wired pipe, a casing, an acoustics pathway through a casing, and a wireline.

14. The system of claim 1, wherein the sensor is selected from a group consisting of: temperature, pressure, chemistry, and vibration.

15. A method of monitoring a downhole condition, comprising:providing power to a downhole instrumentation; andcommunicating with a downhole sensor attached to or embedded in a casing collar, centralizer or wellbore casing to transmit condition data to a user above ground.

16. The method of claim 15, wherein the power is provided one or more power sources selected from the group comprising a permanent magnetic field, a thermoelectric generator, a vibrational energy harvester, an acoustic energy harvester, an electrode metal insert power source, and a wireline.

17. The method of claim 15, wherein communicating is by a communication pathway selected from a group comprising a wired pipe, a casing, an acoustics pathway through a casing, and a wireline.

18. The method of claim 15, wherein the sensor is selected from a group consisting of temperature, pressure, chemistry, and vibration.

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