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Title:
DEVICE FOR GENERATING ELECTRICITY WHILE TRIPPING
Document Type and Number:
WIPO Patent Application WO/2016/153981
Kind Code:
A1
Abstract:
A device for generating electricity, e.g., while tripping into or out of a hole includes a wheel coupled to a dynamo, where a rotation of the wheel causes the dynamo to generate an electrical current. The device can further include a central shaft with an arm extending from the central shaft. The arm may be configured to bring the wheel into contact with an inner surface of a hole while the central shaft is moving, e.g., tripping into or out of the hole, thereby causing the wheel to rotate.

Inventors:
PANARIELLO, Remy (Stonehouse Technology Centre, Building A Brunel Way,Stroudwater Business Park, Stonehouse Gloucestershire GL10 3SX, 3SX, GB)
HERNANDEZ SOLIS, Vladimir (Stonehouse Technology Centre, Building A Brunel Way,Stroudwater Business Park, Stonehouse Gloucestershire GL10 3SX, 3SX, GB)
WARD, Norman (Stonehouse Technology Centre, Building A Brunel Way,Stroudwater Business Park, Stonehouse Gloucestershire GL10 3SX, 3SX, GB)
STOCK, Graham Rupert Rapley (Building A, Brunel WayStroudwater Business Park, Stonehouse Gloucestershire GL10 3SX, 3SX, GB)
Application Number:
US2016/023086
Publication Date:
September 29, 2016
Filing Date:
March 18, 2016
Export Citation:
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Assignee:
SCHLUMBERGER TECHNOLOGY CORPORATION (300 Schlumberger Drive, Sugar Land, Texas, 77478, US)
SCHLUMBERGER CANADA LIMITED (125 - 9 Avenue SE, Calgary, Alberta T2G 0P6, 0P6, CA)
SERVICES PETROLIERS SCHLUMBERGER (42 rue Saint Dominique, Paris, Paris, FR)
SCHLUMBERGER TECHNOLOGY B.V. (Parkstraat 83-89m, JG The Hague, Hague, NL)
International Classes:
E21B41/00; E21B17/00; H02K21/02
Foreign References:
EP0011578A11980-05-28
US20020157904A12002-10-31
EP0233683A21987-08-26
EP2708695A12014-03-19
US7537053B12009-05-26
Attorney, Agent or Firm:
KLINGER, David W. et al. (10001 Richmond Avenue, IP Administration Center of ExcellenceRoom 472, Houston Texas, 77042, US)
Download PDF:
Claims:
What is claimed is:

1. A device, comprising:

a dynamo;

a wheel coupled to the dynamo, a rotation of the wheel causing the dynamo to generate an electrical current;

a central shaft; and

an arm extending from the central shaft, the arm being configured to bring the wheel into contact with an inner surface of a hole, causing the wheel to rotate.

2. The device as recited in claim 1, the dynamo is configured to power downhole equipment or charge an energy storage device with the generated electrical current.

3. The device as recited in claim 1, wherein the arm is further configured to retract to bring the wheel out of contact with the inner surface of the hole.

4. The device as recited in claim 3, wherein the arm is configured to retract until at least a portion of the wheel is no longer protruding from the central shaft. 5. The device as recited in claim 3, further comprising an actuator configured to cause the arm to extend or retract.

6. The device as recited in claim 5, further comprising control circuitry configured to cause the actuator to retract the arm in response to a received command or an indication that a drill assembly coupled to the central shaft is drilling or is going to begin drilling into the hole.

7. The device as recited in claim 1, further comprising a swivel connector coupling the wheel to the arm, the swivel connector enabling the wheel to tilt out of alignment with the central shaft when the central shaft is rotated.

8. The device as recited in claim 1, further comprising at least a second wheel coupled to the dynamo or coupled to a second dynamo.

9. The device as recited in claim 8, further comprising a second arm configured to bring the second wheel into contact with the inner surface of the hole while the central shaft is tripping into or out of the hole, causing the wheel to rotate.

10. The device as recited in claim 9, wherein the second arm is located at an angle about the central shaft from the arm.

11. A system, comprising:

downhole equipment; and

the device recited in any of the preceding claims, wherein the device is configured to generate electricity for utilization by the downhole equipment while the downhole equipment and the device are tripping into or out of a hole.

12. The system as recited in claim 11, further comprising an energy storage device coupled to the device and the downhole equipment, wherein the device is configured to charge the energy storage device with the generated electricity.

13. The system as recited in claim 12, wherein the energy storage device is configured to power the downhole equipment.

14. The system as recited in claim 12, wherein the energy storage device comprises at least one of: a rechargeable battery cell, a rechargeable battery pack, or a capacitor.

15. The system as recited in claim 11, wherein the downhole equipment comprises at least one of: a sensor, an electrical motor, a transmitter, a receiver, a controller, or an energy storage device.

16. A method, comprising:

introducing a central shaft carrying a wheel coupled to a dynamo into a hole;

placing the wheel into contact with an inner surface of the hole; and

raising or lowering the central shaft to cause the wheel to rotate due to resistance on the wheel from the inner surface of the hole, thereby causing the dynamo to generate an electrical current.

17. The method as recited in claim 16, further comprising:

powering downhole equipment with the generated electrical current.

18. The method as recited in claim 16, further comprising:

charging an energy storage device with the generated electrical current.

19. The method as recited in claim 16, wherein placing the wheel into contact with the inner surface of the hole comprises:

extending a retractable arm from the central shaft to bring the wheel into contact with the inner surface of the hole, the retractable arm having a first end coupled to the central shaft and a second end coupled to the wheel.

20. The method as recited in claim 19, further comprising:

retracting the retractable arm to bring the wheel out of contact with the inner surface of the hole in response to a received command or an indication that a drill assembly coupled to the central shaft is drilling or is going to begin drilling into the hole.

Description:
DEVICE FOR GENERATING ELECTRICITY WHILE TRIPPING

CROSS-REFERENCE TO RELATED APPLICATION

This application claims the benefit of and priority to U.S. Provisional Application Serial No.: 62/136,597, filed March 22, 2015, which is incorporated herein by reference in its entirety.

BACKGROUND

Oil wells are created by drilling a hole into the earth, in some cases using a drilling rig that rotates a drill string (e.g., drill pipe) having a drill bit attached thereto. In other cases, the drilling rig does not rotate the drill bit. For example, the drill bit can be rotated downhole. The drill bit, aided by the weight of pipes (e.g., drill collars) cuts into rock within the earth. Drilling fluid (e.g., mud) is pumped into the drill pipe and exits at the drill bit. The drilling fluid may be used to cool the bit, lift rock cuttings to the surface, at least partially prevent destabilization of the rock in the wellbore, and/or at least partially overcome the pressure of fluids inside the rock so that the fluids do not enter the wellbore. Other equipment can also be used for evaluating formations, fluids, production, other operations, and so forth.

Downhole equipment can be powered by remote energy sources that power the equipment via transmission lines (e.g., electrical, optical, mechanical, or hydraulic transmission lines). Downhole equipment can also be powered by local energy sources such as local generators or energy storage devices (e.g., battery packs) coupled with the equipment. In some cases, rechargeable energy storage devices (e.g., rechargeable battery cells or packs) are used to power downhole equipment.

SUMMARY

Aspects of the disclosure can relate to a device for generating electricity, e.g., while tripping into or out of a hole. In embodiments, the device can include a wheel coupled to a dynamo, where a rotation of the wheel causes the dynamo to generate an electrical current. The device can further include a central shaft with an arm extending from the central shaft. The arm may be configured to bring the wheel into contact with an inner surface of a hole while the central shaft is tripping into or out of the hole, thereby causing the wheel to rotate.

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

FIGURES

Embodiments of a device for generating electricity while tripping into or out of a hole are described with reference to the following figures. The same numbers are used throughout the figures to reference like features and components.

FIG. 1 illustrates an example system in which embodiments of a device for generating electricity while tripping can be implemented.

FIG. 2 illustrates various components of an example device that can implement embodiments of a device for generating electricity while tripping.

FIG. 3 illustrates various components of an example device that can implement embodiments of a device for generating electricity while tripping.

FIG. 4 illustrates various components of an example device that can implement embodiments of a device for generating electricity while tripping.

FIG. 5 illustrates various components of an example device that can implement embodiments of an energy storage device configured to be charged by a device for generating electricity while tripping.

FIG. 6 illustrates an example system in which embodiments of a device for generating electricity while tripping can be implemented.

DETAILED DESCRIPTION FIG. 1 depicts a wellsite system 100 in accordance with one or more embodiments of the present disclosure. The wellsite can be onshore or offshore. A borehole 102 is formed in subsurface formations by directional drilling. A drill string 104 extends from a drill rig 106 and is suspended within the borehole 102. In some embodiments, the wellsite system 100 implements directional drilling using a rotary steerable system (RSS). For instance, the drill string 104 is rotated from the surface, and down hole devices move the end of the drill string 104 in a desired direction. The drill rig 106 includes a platform and derrick assembly positioned over the borehole 102. In some embodiments, the drill rig 106 includes a rotary table 108, kelly 110, hook 112, rotary swivel 114, and so forth. For example, the drill string 104 is rotated by the rotary table 108, which engages the kelly 110 at the upper end of the drill string 104. The drill string 104 is suspended from the hook 112 using the rotary swivel 114, which permits rotation of the drill string 104 relative to the hook 112. However, this configuration is provided by way of example and is not meant to limit the present disclosure. For instance, in other embodiments a top drive system is used.

A bottom hole assembly (BHA) 116 is suspended at the end of the drill string 104. The bottom hole assembly 116 includes a drill bit 118 at its lower end. In embodiments of the disclosure, the drill string 104 includes a number of drill pipes 120 that extend the bottom hole assembly 116 and the drill bit 118 into subterranean formations. Drilling fluid (e.g., mud) 122 is stored in a tank and/or a pit 124 formed at the wellsite. The drilling fluid can be water-based, oil- based, and so on. A pump 126 displaces the drilling fluid 122 to an interior passage of the drill string 104 via, for example, a port in the rotary swivel 114, causing the drilling fluid 122 to flow downwardly through the drill string 104 as indicated by directional arrow 128. The drilling fluid 122 exits the drill string 104 via ports (e.g., courses, nozzles) in the drill bit 118, and then circulates upwardly through the annulus region between the outside of the drill string 104 and the wall of the borehole 102, as indicated by directional arrows 130. In this manner, the drilling fluid 122 cools and lubricates the drill bit 118 and carries drill cuttings generated by the drill bit 118 up to the surface (e.g., as the drilling fluid 122 is returned to the pit 124 for recirculation).

In some embodiments, the bottom hole assembly 116 includes a logging-while-drilling (LWD) module 132, a measuring-while-drilling (MWD) module 134, a rotary steerable system 136, a motor, and so forth (e.g., in addition to the drill bit 118). The logging-while-drilling module 132 can be housed in a drill collar and can contain one or a number of logging tools. It should also be noted that more than one LWD module and/or MWD module can be employed (e.g. as represented by another logging-while-drilling module 138). In embodiments of the disclosure, the logging-while drilling modules 132 and/or 138 include capabilities for measuring, processing, and storing information, as well as for communicating with surface equipment, and so forth.

The measuring-while-drilling module 134 can also be housed in a drill collar, and can contain one or more devices for measuring characteristics of the drill string 104 and drill bit 118. The measuring- while-drilling module 134 can also include components for generating electrical power for the down hole equipment. This can include a mud turbine generator (also referred to as a "mud motor") powered by the flow of the drilling fluid 122. However, this configuration is provided by way of example and is not meant to limit the present disclosure. In other embodiments, other power and/or battery systems can be employed. The measuring- while-drilling module 134 can include one or more of the following measuring devices: a weight-on-bit measuring device, a torque measuring device, a vibration measuring device, a shock measuring device, a stick slip measuring device, a direction measuring device, an inclination measuring device, and so on. In embodiments of the disclosure, the wellsite system 100 is used with controlled steering or directional drilling. For example, the rotary steerable system 136 is used for directional drilling. As used herein, the term "directional drilling" describes intentional deviation of the wellbore from the path it would naturally take. Thus, directional drilling refers to steering the drill string 104 so that it travels in a desired direction. In some embodiments, directional drilling is used for offshore drilling (e.g., where multiple wells are drilled from a single platform). In other embodiments, directional drilling enables horizontal drilling through a reservoir, which enables a longer length of the wellbore to traverse the reservoir, increasing the production rate from the well. Further, directional drilling may be used in vertical drilling operations. For example, the drill bit 118 may veer off of a planned drilling trajectory because of the unpredictable nature of the formations being penetrated or the varying forces that the drill bit 118 experiences. When such deviation occurs, the wellsite system 100 may be used to guide the drill bit 118 back on course.

Drill assemblies can be used with, for example, a wellsite system (e.g., the wellsite system 100 described with reference to FIG. 1). For instance, a drill assembly can comprise a bottom hole assembly suspended at the end of a drill string (e.g., in the manner of the bottom hole assembly 116 suspended from the drill string 104 depicted in FIG. 1). In some embodiments, a drill assembly is implemented using a drill bit. However, this configuration is provided by way of example and is not meant to limit the present disclosure. In other embodiments, different working implement configurations are used. Further, use of drill assemblies in accordance with the present disclosure is not limited to wellsite systems described herein. Drill assemblies can be used in other various cutting and/or crushing applications, including earth boring applications employing rock scraping, crushing, cutting, and so forth.

A drill assembly includes a body for receiving a flow of drilling fluid. The body comprises one or more crushing and/or cutting implements, such as conical cutters and/or bit cones having spiked teeth (e.g., in the manner of a roller-cone bit). In this configuration, as the drill string is rotated, the bit cones roll along the bottom of the borehole in a circular motion. As they roll, new teeth come in contact with the bottom of the borehole, crushing the rock immediately below and around the bit tooth. As the cone continues to roll, the tooth then lifts off the bottom of the hole and a high-velocity drilling fluid jet strikes the crushed rock chips to remove them from the bottom of the borehole and up the annulus. As this occurs, another tooth makes contact with the bottom of the borehole and creates new rock chips. In this manner, the process of chipping the rock and removing the small rock chips with the fluid jets is continuous. The teeth intermesh on the cones, which helps clean the cones and enables larger teeth to be used. A drill assembly comprising a conical cutter can be implemented as a steel milled-tooth bit, a carbide insert bit, and so forth. However, roller-cone bits are provided by way of example and are not meant to limit the present disclosure. In other embodiments, a drill assembly is arranged differently. For example, the body of the bit comprises one or more polycrystalline diamond compact (PDC) cutters that shear rock with a continuous scraping motion.

In embodiments of the disclosure, the body of a drill assembly can define one or more nozzles that allow the drilling fluid to exit the body (e.g., proximate to the crushing and/or cutting implements). The nozzles allow drilling fluid pumped through, for example, a drill string to exit the body. For example, drilling fluid can be furnished to an interior passage of the drill string by the pump and flow downwardly through the drill string to a drill bit of the bottom hole assembly, which can be implemented using, for example, a drill assembly. Drilling fluid then exits the drill string via nozzles in the drill bit, and circulates upwardly through the annulus region between the outside of the drill string and the wall of the borehole. In this manner, rock cuttings can be lifted to the surface, destabilization of rock in the wellbore can be at least partially prevented, the pressure of fluids inside the rock can be at least partially overcome so that the fluids do not enter the wellbore, and so forth.

Modern oil and gas exploration increasingly uses electronic devices in the borehole to provide measurements, and for control and operational optimization. When operating electronics as part of a drill string and/or other downhole equipment and/or strings (e.g., for well testing, well simulation, well monitoring, formation evaluation, etc.), available power in the borehole may be limited near a bottom hole assembly. Energy storage devices (e.g., battery cells, battery packs, capacitors, energy cells, and the like) can also be installed in electronic equipment to provide electrical power in a borehole. Yet, batteries have a finite energy storage capacity, which limits the amount of time the equipment can be operated. In some cases, larger batteries may be used, but the amount of space available in the borehole is also finite, limiting the size of such batteries. In other cases, higher power density batteries may be used, but such batteries may be more prone to failure (e.g., in the high temperature operating conditions present downhole). FIGS. 2 through 4 illustrate embodiments of a device 200 for generating electricity while tripping. The term "tripping" often refers to the act of running a drill string into or pulling a drill string out of a wellbore. Tripping pipe can be performed for a variety of reasons. For example reasons for tripping pipe can include replacing a worn-out drill bit, replacing damaged drill pipe, repairing downhole equipment, and so forth. As used herein, the term "tripping" can include any travel into or out of a hole (e.g., wellbore). For example, tripping the device 200 into the hole can include lowering the device 200 downwards to a depth within the hole, and tripping the device 200 out of the hole can include raising the device 200 upwards towards the surface from a depth within the hole. In embodiments, the device 200 can be implemented in a drill string (e.g., as shown in FIGS. 1 and 6). For example, the device 200 can be included in or coupled to the bottom hole assembly 116.

In some embodiments, a bottom hole assembly 116 can include downhole equipment powered by the device 200 with electricity generated by the device 200 while tripping or with electricity from an energy storage device that can be recharged by the device 200 while the bottom hole assembly 116 is tripping into or out of a hole (e.g., a wellbore). For example, downhole equipment powered by the device 200 or by a rechargeable energy storage device can include a sensor, an actuator (e.g., motor, servo, or switch), a transmitter, a receiver, a controller, or the like. In some embodiments, the downhole equipment can include one or more components of the logging-while-drilling (LWD) module 132, the measuring-while-drilling (MWD) module 134, the rotary steerable system 136, and so forth. In some embodiments, the device 200 can be used to heat energy storage devices while tripping in or tripping out of the hole. For example, downhole batteries can be manufactured to withstand high temperatures (e.g., above 100°C), but these batteries may not work well at lower temperatures (e.g., below 50 °C). The electricity generated by the device 200 while tripping can be used to heat batteries to an effective operating temperature. The device 200 can be directly coupled (e.g., via a wired connection) to an energy storage device or downhole equipment. The device 200 can also be optically or electromagnetically coupled with the energy storage device or the downhole equipment. Although a wellsite drilling system 100 is described herein, those skilled in the art will appreciate that any system can include electronic equipment (e.g., sensors, actuators, communication devices, controllers, energy storage device, or the like) which may be powered by the device 200 with electricity generated by the device 200 while tripping or with electricity from an energy storage device that can be recharged by the device 200 while tripping into or out of a hole, through a tunnel, or any other passage having at least one inner surface.

In an embodiment shown in FIG 3, the device 200 is shown to include a shaft 1 with at least one arm 3 extending outwards from the shaft 1. In some embodiments, the shaft 1 can be included as a sub-assembly of the bottom hole assembly 116 or can be coupled to the bottom hole assembly 116. The device 200 further includes at least one wheel 2 coupled to the arm 3. In some embodiments, the device 200 includes several wheels 2 which may be coupled to respective arms 3. In embodiments where the device 200 includes multiple arms 3 with respective wheels 2 coupled to the arms 3, the arms 3 can be configured to extend outwards from the shaft in different directions. For example, a first arm 3, when extended, may be positioned at an angle about the shaft 1 relative to a second arm 3. In an embodiment shown in FIG. 2, the arms 3 can be configured to extend in opposite directions (e.g., 180° about the shaft 1). The one or more wheels 2 can include a saw-toothed or gear-like edge (i.e., the rotating edge) to enable the one or more wheels 2 to grip and rotate against an inner surface of a hole (e.g., inner walls of a wellbore).

In some embodiments, the arms 3 are retractable. For example, the arms 3 may be configured to retract inwards towards the shaft 1 or extend outwards away from the shaft 1. The arms 3 can extend outwards away from the shaft 1 to place the wheels 2 into contact with the inner surface of the hole. In other embodiments, the arms 3 may be fixed in an extended configuration. In some embodiments, the wheels 2 can be coupled to the arms 3 with swivel connectors that enable the wheels 2 to tilt out of alignment with the shaft 1 when the shaft 1 is rotated. This can protect the wheels 2 from damage if the shaft 1 is rotated while tripping or if the wheels 2 remain in contact with the inner surface of the hole while drilling.

In embodiments where the arms 3 are retractable, an actuator can be configured to extend or retract the arms 3. For example, the arms 3 can include or may be driven by spring-loaded calipers. The actuator can also include a motor or linear actuator configured to drive the arms 3 inwards or outwards from the shaft 1. In some embodiments, one or more actuators can extend one or more arms 3 an outward distance from the shaft 1 to place one or more respective wheels 2 into contact with the inner surface of the hole. The one or more actuators can be further configured to retract the one or more arms 3 to bring the wheels 2 out of contact with the inner surface of the hole. In some embodiments, each arm 3 is configured to retract until at least a portion of the respective wheel 2 is no longer protruding from the central shaft 1. Control circuitry 4 (e.g., a processor, controller, programmable logic device, circuit of discrete logic components, or the like) or a mechanical switch (e.g., movement or flow triggered flap or lever) can be configured to cause the actuator to retract the arms 3 in response to an indication that a drill assembly is drilling into the hole (e.g., pumps are on and/or BHA is rotating) or in response to an indication the drill assembly will begin drilling into the hole.

The one or more wheels 2 can be coupled to one or more dynamos 5 configured to generate an electrical current (e.g., DC current) when the one or more wheels 2 rotate due to resistance from the inner surface of the hole while tripping into or out of the hole. For example, each wheel 2 may be coupled with a commutator of a respective dynamo 5 or multiple wheels 2 may be coupled to gears configured to rotate one or more commutators of one or more dynamos 5. In some embodiments, control circuitry 4 can include a voltage and/or current manager configured to smooth out current and voltage fluctuations. The control circuitry 4 can also include one or more temperature sensors, and may be configured to deactivate energy harvesting or cause the actuator to retract the arms 3 when a temperature above a threshold temperature is detected.

FIG. 5 illustrates an embodiment of an energy storage device 208 (e.g., rechargeable battery) that can be recharged with current generated by the dynamos 5 when the wheels 2 are rotated while the device 200 is tripping into or out of the hole. In some embodiments, the energy storage device can include a lithium-polymer chemistry cell (CRC). Using the device 200, the energy storage device can be surface and downhole charged. Further, electricity generated by the device 200 can be used to heat the energy storage device to an appropriate operating range. For example, some batteries have an operational range of approximately 50°C to 150°C, and as such, these batteries may be non-operational near the surface where lower temperatures (e.g., below 50°C) may be encountered. Thus, in addition to being able to recharge energy storage devices while tripping, the device 200 can further enable the energy storage device to be used while tripping when the energy storage device is subject to a temperature below an appropriate operating temperature of the energy storage device. An embodiment of a system 300 including the device 200 is shown in FIG. 6, where a drill string 202 is configured to carry the device 200, a battery compartment 204, and a bottom hole assembly (BHA) 206 into a wellbore. Examples of operational modes that can be controlled (e.g., via control circuitry 4) are described below. In an example mode of operation while tripping into the hole at low temperature, the BHA 206 is moved downhole. As there is no flow, the wheels 2 can be brought into contact with the inner surface of the hole, causing the wheels 2 to rotate. If an energy storage device 208 (e.g., CRC battery) is not subject to an operational temperature, power can be sustained by the device 200, by a different energy source (e.g., non-rechargeable lithium thionyl chloride (LTC) batteries), or the device 200 can supply energy to a heating system to heat up the energy storage device to a suitable operating temperature.

In another example mode of operation while tripping into the hole at high temperature, the BHA 206 is moved downhole. When the temperature is within an operational range of a rechargeable energy storage device 208, the control circuitry 4 can be configured to cause the device 200 to generate electricity or direct electricity being generated by the device 200 to the rechargeable energy storage device. When the rechargeable energy storage device is fully charged, the control circuitry 4 can cause the device 200 to power downhole equipment or can cause the charged energy storage device to power the downhole equipment while a second rechargeable energy storage device is recharged by the device 200.

In another example mode of operation, while drilling, the BHA 206 is rotating. To avoid damage to the device 200, the control circuitry 4 or a mechanical switch can cause the arms to retract, thereby bringing the wheels 2 away from the inner surface of the hole. Power can be supplied by a local energy storage device (e.g., a charged CRC battery or an LTC battery).

In another example mode of operation, while tripping out of the hole at high temperature, the BHA 206 is moved upwards towards the surface. When the drilling has ceased, the control circuitry 4 or a mechanical switch can cause the arms to extend, thereby bringing the wheels 2 into contact with the inner surface of the hole. When the temperature is within an operational range of a rechargeable energy storage device 208, the control circuitry 4 can be configured to cause the device 200 to generate electricity or direct electricity being generated by the device 200 to the rechargeable energy storage device 208. When the rechargeable energy storage device 208 is fully charged, the control circuitry 4 can cause the device 200 to power downhole equipment or can cause the charged energy storage device 208 to power the downhole equipment while a second rechargeable energy storage device is recharged by the device 200. In another example mode of operation, while tripping out of the hole at low temperature, the BHA 206 is moved upwards towards the surface. Because of heat inertia, the internal temperature of a rechargeable energy storage device 208 can be at an operational level despite being subject to a non-operational external temperature. If the energy storage device (e.g., CRC battery) becomes non-operational due to heat loss, power can be sustained by the device 200, by a different energy source (e.g., non-rechargeable LTC batteries), or the device 200 can supply energy to a heating system to heat up the energy storage device to a suitable operating temperature.

Although a few example embodiments have been described in detail above, those skilled in the art will readily appreciate that many modifications are possible in the example embodiments without materially departing from the disclosure. Additionally, it should be understood that references to "one embodiment" or "an embodiment" of the present disclosure are not intended to be interpreted as excluding the existence of additional embodiments that also incorporate the recited features. For example, features shown in individual embodiments referred to above may be used together in combinations other than those which have been shown and described specifically. Accordingly, any such modification is intended to be included within the scope of this disclosure. In the claims, means-plus-function clauses are intended to cover the structures described herein as performing the recited function and not just structural equivalents, but also equivalent structures. Thus, although a nail and a screw may not be structural equivalents in that a nail employs a cylindrical surface to secure wooden parts together, whereas a screw employs a helical surface, in the environment of fastening wooden parts, a nail and a screw may be equivalent structures. It is the express intention of the applicant not to invoke means-plus-function for any limitations of any of the claims herein, except for those in which the claim expressly uses the words 'means for' together with an associated function.