Stand by power system for well system electrification

Abstract

A technique facilitates reliable operation of a blowout preventer (BOP) system in a wide range of challenging environments. The BOP system is an electrical system comprising electrically powered components. The electrically powered components are connected with a primary energy storage device which provides electric power for operating those components. Additionally, a secondary energy storage device may be connected to the primary energy storage device in a manner so as to maintain a desired level of charge on the primary energy storage device. The secondary energy storage device has a longer lifespan and a lower discharge rate compared to the primary energy storage device. By way of example, the secondary energy storage device may be in the form of a secondary battery which is nuclear powered.

Description

STAND BY POWER SYSTEM FOR WELL SYSTEM ELECTRIFICATIONCROSS-REFERENCE TO RELATED APPLICATION

[0001] The present document is based on and claims priority to US Provisional Patent Application No. 63 / 733759, filed December 13, 2024, which is incorporated herein by reference in its entirety.BACKGROUND

[0002] In many oil and gas well applications, various types of equipment may be used to contain and isolate pressure in the wellbore. For example, a blowout preventer system may be installed subsea on a wellhead to protect against blowouts. The blowout preventer has a longitudinal interior passage which allows passage of pipe, e.g. drill pipe, and other well components. Additionally, the blowout preventer has a variety of features including rams, e.g. blowout preventer pipe rams and shear rams, which facilitate rapid well closing and sealing operations. Control over operation of the blowout preventer generally is achieved with various types of hydraulic controls. However, as deeper subsea wells and various other types of wells are developed, the blowout preventer systems are required to operate in more challenging environments which can render the hydraulic operating system susceptible to failure. An electrically powered system may address some of these reliability issues but difficulty arises in maintaining a supply of electrical power at the well, e.g. at a deep subsea well.SUMMARY

[0003] In general, a system and method facilitate reliable operation of a blowout preventer (BOP) system in a wide range of challenging environments. The BOP system described herein is an electrical system comprising electrically powered components. The electrically powered components are connected with a primary energy storage devicewhich provides electric power for operating those components. Additionally, a secondary energy storage device may be connected to the primary energy storage device in a manner so as to maintain a desired level of charge on the primary energy storage device. The secondary energy storage device has a longer lifespan and a lower discharge rate compared to the primary energy storage device. By way of example, the secondary energy storage device may be in the form of a secondary battery which is nuclear powered.

[0004] However, many modifications are possible without materially departing from the teachings of this disclosure. Accordingly, such modifications are intended to be included within the scope of this disclosure as defined in the claims.BRIEF DESCRIPTION OF THE DRAWINGS

[0005] Certain embodiments of the disclosure will hereafter be described with reference to the accompanying drawings, wherein like reference numerals denote like elements. It should be understood, however, that the accompanying figures illustrate the various implementations described herein and are not meant to limit the scope of various technologies described herein, and:

[0006] Figure 1 is an illustration of an example of an electrically powered BOP system mounted on a wellhead above a borehole, according to an embodiment of the disclosure;

[0007] Figure 2 is a cross-sectional illustration of a portion of the electrically powered BOP system which includes an example of an electrically powered annular closing system, according to an embodiment of the disclosure;

[0008] Figure 3 is an illustration of an example of an electrical power system positioned at the BOP system to provide electrical power for operation of the BOP system, according to an embodiment of the disclosure;

[0009] Figure 4 is an illustration of another example of the electrical power system, according to an embodiment of the disclosure; and

[0010] Figure 5 is an illustration of an example of stackable battery modules which may be used in the electric power system and numbered according to the desired power output, according to an embodiment of the disclosure.DETAILED DESCRIPTION

[0011] In the following description, numerous details are set forth to provide an understanding of some embodiments of the present disclosure. However, it will be understood by those of ordinary skill in the art that the system and / or methodology may be practiced without these details and that numerous variations or modifications from the described embodiments may be possible.

[0012] The disclosure herein generally involves a system and method which facilitate reliable operation of a blowout preventer (BOP) system in a wide range of challenging environments. The BOP system is an electrical system comprising electrically powered components which are connected with a primary energy storage device. The primary energy storage device provides electric power for operating, e.g., actuating, those components. According to an embodiment, a secondary energy storage device may be connected to the primary energy storage device in a manner so as to maintain a desired level of charge on the primary energy storage device. The secondary energy storage device has a longer lifespan and a lower discharge rate compared to the primary energy storage device. By way of example, the secondary energy storage device may be in the form of a secondary battery which is nuclear powered.

[0013] The primary energy storage device may be constructed from one or more batteries able to provide sufficient power and discharge rate to operate various types of electrically powered components, such as electric motors, electric BOPs, valves, annularclosing systems, and / or other types of electrically powered components. Various types of batteries may be employed to provide the desired power. Examples of such batteries include lithium ion batteries, lithium polymer batteries, nickel metal hydride batteries, and other suitable batteries.

[0014] The secondary energy storage device also may comprise one or more batteries but such batteries are selected and constructed to provide a lower discharge rate over a long lifespan so as to maintain a desired level of charge on the primary energy storage device. In other words, the secondary energy storage device is used to provide a trickle charge which maintains the primary energy storage device at sufficient charge for operation of the electrically powered components. In subsea applications, the long lifespan of the secondary energy storage device enables long-term operation of a subsea BOP system without retrieving components to the surface and without running power cable from the surface.

[0015] By way of example, the secondary energy storage device may comprise nuclear powered batteries which can have a life span of several decades. Nuclear powered batteries are sometimes referred to as atomic batteries or radioactive decay batteries. In some embodiments, each nuclear battery combines thermocouples and radioactive isotopes which undergo spontaneous radioactive decay. During this radioactive decay, the radioactive isotopes emit radiation, thus generating heat upon being absorbed by a suitable substance.

[0016] The heat is converted into electricity via the thermocouple or thermocouples. These batteries function by a process known as the Seebeck effect where dissimilar metals joined together (i.e. a thermocouple) are heated and thus generate an electromotive force and thereby create electricity which can be used to charge the primary energy storage device. Because of this process of creating electricity, these types of nuclear batteries are sometimes referred to as radioisotope thermoelectric generators. Various types of radioisotopes may be used in constructing the nuclear batteries so as to provide the desired discharge over a long period of time.

[0017] The primary energy storage device and the secondary energy storage device are positioned locally at a wellsite to provide electricity for the BOP system, e.g. a BOP stack. In some embodiments, one or both of the primary energy storage device and the secondary energy storage device may be mounted on the BOP stack. The BOP system may be in the form of a surface system or a subsea system. Subsea systems, however, particularly benefit from having power generation local to the wellsite. With subsea BOP systems, the use of nuclear batteries in the secondary energy storage device enables sufficient charge to be maintained on the primary energy storage device without any independent connection to the surface.

[0018] It should be noted that depending on the power requirements and the types of batteries employed, some embodiments of the BOP system may utilize nuclear powered batteries without using a separate energy storage device constructed with conventional batteries. Additionally, each of the primary energy storage device and the secondary energy storage device may be constructed as stackable systems. With stackable systems, battery modules may be coupled together, e.g. stacked, to achieve a desired power capability, discharge rate, battery life, or to achieve other power related parameters for operating the electric BOP system.

[0019] Referring generally to Figure 1, a well system 30 is illustrated as comprising a BOP system 32 for providing pressure control at a well 33. In this example, the BOP system 32 is mounted on a wellhead 34, e.g., a land-based wellhead or a subsea wellhead, located above a borehole 35, e.g., a wellbore. The BOP system 32 may be arranged as a BOP stack 36 and may comprise a variety of BOP components, such as hydraulic or electric BOPs 38 and an annular closing system 40. By way of example, the BOPs 38 may comprise pipe rams and shear rams. Additionally, the annular closing system 40 may be mounted above the ram BOPs 38.

[0020] In the embodiment illustrated, BOP system 32 is an electric BOP system which utilizes electric power for operating, e g., actuating, various electrically poweredcomponents such as BOPs 38 and annular closing system 40. It should be noted that in some embodiments, the BOPs 38 are directly actuated electrically, i.e,. electric BOPs 38. However, in other embodiments the BOPs 38 may be indirectly actuated electrically via electric actuators employed to drive hydraulic actuating fluid to hydraulic BOPs 38. Similarly, the annular closing system 40 may be directly or indirectly actuated electrically.

[0021] Electric power is provided to the electrically powered components 38, 40 via an electric power system 42. In the embodiment illustrated, the electric power system 42 is positioned locally at the well 33, e.g., at the wellsite. In some embodiments, electric power system 42 may be mounted on the BOP stack 36 or at another suitable location local to BOP system 32. According to an example, the electric power system 42 comprises a primary energy storage device 44 which is connected to the electrically powered components, e.g., components 38, 40, to provide sufficient electric power for operation of those components.

[0022] In the illustrated embodiment, electric power system 42 also comprises a secondary energy storage device 46 which is connected to the primary energy storage device 44 in a manner which maintains a desired level of charge on the primary energy storage device 44. In other words, the secondary energy storage device 46 may be used as a trickle charger for the primary energy storage device 44. To enable long-term operation of BOP system 32, the secondary energy storage device 46 may be constructed so as to have a lower discharge rate but a longer lifespan compared to the primary energy storage device 44. As described in greater detail below, the secondary energy storage device 46 may be constructed with one or more nuclear powered batteries to potentially provide decades of uninterrupted service.

[0023] To accommodate movement of components into borehole 35, the BOP system 32 may have a central, longitudinal passage. The central, longitudinal passage is sized to enable movement of tubular components 47, e.g., drill pipe or other pipe,therethrough. Various other types of tubular components, tools, fluids, and other well related items may be moved through BOP system 32 via the central, longitudinal passage.

[0024] Referring generally to Figure 2, one example of electronic annular closing system 40 is illustrated as being electrically actuatable via at least one electrically operated rotary-to-linear actuator 48. In the specific example illustrated, a plurality of the rotary-to-linear actuators 48 may be employed to cause the desired actuation of annular closing system 40 upon appropriate electrical power input. According to the example illustrated, the annular closing system 40 comprises an annular body 50 which forms the outer structure that supports components of annular closing system 40. In this embodiment, the electrically operated rotary-to-linear actuators 48 are mounted completely within annular body 50 via suitable mounting structures 52, e.g., appropriately sized passages through a base of annular body 50.

[0025] In this particular embodiment, a pusher mechanism 54 is mounted in engagement with corresponding pusher rods 56 of electrically operated rotary-to-linear actuators 48. By way of example, the pusher mechanism 54 may be in the form of (or may comprise) a pusher plate 58 against which the pusher rods 56 abut or are otherwise engaged. In some embodiments, the pusher mechanism 54 is engaged by a plurality of the pusher rods 56 which are arranged around a central passageway 60. It should be noted the central passageway 60 is a continuation of the internal passageway extending through BOP system 32.

[0026] In the illustrated example, the pusher mechanism 54 / 58 is linearly slidable in a direction generally parallel with an axis 62 of central passageway 60 while being secured radially between a central body mounting structure 64 and a top structure 66. The top structure 66 may be secured to annular body 50 via, for example, an actuator ring 68 or other suitable fastening mechanism.

[0027] According to the embodiment illustrated, the top structure 66 cooperates with annular body 50 to secure a packer 70 therein above the central body mountingstructure 64. Packer 70 may have a variety of configurations, but one example utilizes a combination of an elastomeric sealing portion 72 and a metal portion 74, e.g., a steel portion, formed by packer inserts 76 and / or other packer supporting structures. In the illustrated embodiment, packer 70 is surrounded by a donut 78 which may be formed of an elastomeric material or other suitable material able to help form a secure seal within the annular closing system 44.

[0028] As illustrated, the pusher mechanism 54 is movably positioned between the pusher rods 56 of electrically operated rotary-to-linear actuators 48 and the donut 78. Additionally, the donut 78 is constrained via an internal wall 80 of top structure 66. Accordingly, when pusher rods 56 are linearly actuated via electrically operated rotary- to-linear actuators 48, the pusher mechanism 54 is moved in a linear direction toward donut 78, e.g., in a direction parallel with axis 62. This linear movement of pusher mechanism 54 causes the elastomeric donut 78 to be squeezed.

[0029] This squeezing action within the constraints of internal wall 80 further causes the donut 78 to expand radially inwardly and to thus drive the packer 70 in a radially inward direction. Upon sufficient squeezing of donut 78, the packer 70 is forced to a set, sealed position against tubular 47 or to a sealed position within an empty central passageway 60. Regardless, flow along central passageway 60 is blocked once the packer 70 is actuated to the set / closed position.

[0030] It should be noted the electronic annular closing system 40 may be connected to various other components which may be part of the overall BOP system 32. Accordingly, the electronic annular closing system 40 may comprise mounting features 82 constructed for coupling with adjacent components. Examples of mounting features 82 include flanges 84, mounting studs / bolts, or other mounting features.

[0031] By way of example, each electrically operated rotary-to-linear actuator 48 may comprise a motor assembly 86 which works in cooperation with a screw assembly 88. The motor assemblies 86 receive appropriate electrical power from electric powersystem 42 so as to drive the corresponding screw assemblies 88 during actuation of the annular closing system 40. In the embodiment illustrated, each motor assembly 86 and screw assembly 88 is mounted internally within annular body 50. In other words, the motor assemblies 86 and screw assemblies 88 do not extend externally of an outer surface 90 of annular body 50.

[0032] In the example illustrated, the number of motor assemblies 86 matches the number of screw assemblies 88, e.g. five of each, however some embodiments may utilize mismatched numbers of motor assemblies 86 and screw assemblies 88. It should be noted the number of motor assemblies 86 and screw assemblies 88 may vary depending on the parameters of a given operation. Additionally, the actuation of screw assemblies 88 via motor assemblies 86 may be synchronized by using a timing gear 92, e.g., a timing ring gear, which synchronizes the action of the screw assemblies 88 in response to operation of the motor assemblies 86.

[0033] Referring generally to Figure 3, an embodiment is illustrated in which BOPs 38 are indirectly electrically actuated. In this example, the BOPs 38 are selectively actuated between operational positions via hydraulic actuating fluid supplied under pressure via hydraulic lines 94. However, the hydraulic actuating fluid is pressurized via electronic actuators 96 located on or at BOP stack 36 and powered via electric power system 42.

[0034] The electronic actuators 96 may have various configurations, but one example comprises electric motors 98 positioned between a hydraulic piston actuation side 100 and a hydraulic compensation side 102. Each electric motor 98 may be used to, for example, turn a roller screw which cooperates with a linear actuator to drive a corresponding piston for pressurizing the hydraulic actuating fluid. The hydraulic compensation side 102 uses a corresponding piston or other mechanism to enable compensation for the change in volume of hydraulic actuating fluid within the electronic actuators 96.

[0035] In this example, the electric power system 42 comprises primary energy storage device 44 which may be constructed with one or more batteries 104. Furthermore, the electric power system 42 comprises secondary energy device 46 which may be constructed with one or more nuclear batteries 106. The size, configuration, number, coupling system, and chemical structure of the primary and secondary energy storage devices 44, 46 may vary. However, examples include primary batteries 104 in the form of lithium ion batteries, lithium polymer batteries, nickel metal hydride batteries, or other suitable batteries. By way of further example, the secondary nuclear batteries 106 may comprise radioactive decay batteries combining thermocouples and radioactive isotopes which undergo spontaneous radioactive decay as described above.

[0036] The secondary energy storage device 46 may be electrically coupled with the primary energy storage device 44 via a suitable coupling 108. Additionally, the primary energy storage device 44 may be connected to desired electrically powered components via suitable electric lines 110. For example, electric lines 110 may be used to provide electric power to electric motors 98. Other electric lines 110 may be used to provide electric power to other components, e.g., annular closing system 40 or various valves, sensors, and equipment that may be included in a given BOP system 32. Additionally, the system may comprise a variety of other features, such as connector lines 112 which may be used to facilitate POD functions and / or ROV functions.

[0037] Referring generally to Figure 4, another example is illustrated in which the secondary energy storage device 46 comprises a plurality of the secondary nuclear batteries 106. It should be noted that other types of batteries can potentially be used to construct the secondary energy storage device 46, but secondary nuclear batteries 106 provide the desired longevity for operation in a variety of environments, such as subsea environments.

[0038] Furthermore, some BOP stack configurations may obtain sufficient power from appropriately designed and constructed nuclear batteries 106. In such an embodiment, the energy storage device 44 (shown in dashed lines) could be omitted sothat only a single energy storage device is employed. Tn the example of Figure 4, the primary energy storage device 44 is illustrated by the dashed lines as having a plurality of primary batteries 104. The number of primary batteries 104, as well as the number of nuclear batteries 106, can be selected according to the power requirements of a given well application, e.g., of a given BOP stack 36.

[0039] For example, the BOPs 38 illustrated in Figure 4 are in the form of electric BOPs 38 which are electrically actuated directly via electrical power supplied via electric lines 114. The number of primary batteries 104 may be selected to provide the desired electrical power for reliable actuation of the electric BOPs 38. To facilitate adaptability, the batteries 104 and / or batteries 106 may be constructed as battery modules 116 which are readily stacked or otherwise coupled together, as illustrated in Figure 5. This modularity enables easy adaptation of the primary energy storage device 44 and / or secondary energy storage device 46 to achieve a desired electric power capability for each of the primary and secondary devices.

[0040] Additionally, the primary energy storage device 44 may be constructed as two or more primary energy storage devices 44 which are separately charged. This enables, for example, one of the primary energy storage devices 44 to be placed on standby for operation of the electrically powered components while the other primary energy storage device 44 is being charged. The secondary energy storage device 46, e g., nuclear batteries 106, may be connected to the two or more primary energy storage devices 44. Alternatively, two or more of the secondary energy storage devices 46 may be employed to charge corresponding primary energy storage devices 44.

[0041] Depending on the specific well operation, well environment, and well equipment, the overall well system 30 may be adjusted and various configurations may be employed. For example, the BOP system 32 may comprise many types of alternate and / or additional components. Additionally, the BOP system 32 may be combined with many other types of wellheads and other well components used in, for example, land- based or subsea hydrocarbon production operations.

[0042] Furthermore, the components and arrangement of electric power system 42 may vary according to the parameters of a given environment and / or well operation. For example, the electric power system 42 may be constructed with various arrangements of primary energy storage devices 44 and secondary energy storage devices 46. In some applications, a single energy storage device may be sufficient to supply the desired electrical power. Additionally, the primary and secondary energy storage devices may be constructed from various types of batteries able to provide the desired electrical output.

[0043] Although a few embodiments of the disclosure have been described in detail above, those of ordinary skill in the art will readily appreciate that many modifications are possible without materially departing from the teachings of this disclosure. Accordingly, such modifications are intended to be included within the scope of this disclosure as defined in the claims.

Claims

CLAIMSWhat is claimed is:

1. A system for providing electric power at a wellsite, comprising: a blowout preventer (BOP) system having electrically powered components; a primary energy storage device located at the wellsite and connected to the electrically powered components to provide electric power for operating the electrically powered components; and a secondary energy storage device having a longer lifespan and a lower discharge rate compared to the primary energy storage device, the secondary energy storage device being connected to the primary energy storage device in a manner to maintain a desired level of charge on the primary energy storage device.

2. The system as recited in claim 1, wherein the primary energy storage device comprises a primary battery and the secondary energy storage device comprises a secondary battery.

3. The system as recited in claim 2, wherein at least the secondary battery is nuclear powered.

4. The system as recited in claim 1, wherein the BOP system is a subsea BOP system having a BOP stack, the primary energy storage device and the secondary energy storage device being mounted in the BOP stack.

5. The system as recited in claim 1, wherein the electrically powered components comprise at least one rotary-to-linear actuator.

6. The system as recited in claim 1, wherein the electrically powered components comprise at least two rotary-to-linear actuators.

7. The system as recited in claim 3, wherein the secondary battery is a radioactive decay battery.

8. The system as recited in claim 7, wherein the radioactive decay battery utilizes radioactive isotopes.

9. The system as recited in claim 1, wherein the electrically powered components comprise electric BOPs.

10. A system, comprising: a blowout preventer (BOP) system having electrically powered components; a primary energy storage device located at the wellsite and connected to the electrically powered components to provide electric power for operating the electrically powered components; and a secondary energy storage device in the form of a secondary battery which is nuclear powered, the secondary energy storage device being connected to the primary energy storage device to maintain a desired level of charge on the primary energy storage device.

11. The system as recited in claim 10, wherein the BOP system is a subsea BOP system.

12. The system as recited in claim 11, wherein the electrically powered components comprise electric BOPs.

13. The system as recited in claim 10, wherein the electrically powered components comprise at least one rotary-to-linear actuator.

14. The system as recited in claim 10, wherein the electrically powered components comprise at least two rotary-to-linear actuators.

15. The system as recited in claim 10, wherein the secondary battery comprises a radioactive decay battery.

16. The system as recited in claim 15, wherein the radioactive decay battery utilizes radioactive isotopes.

17. A method, comprising: providing a BOP system with electrically operated components; locating a primary energy storage device at a wellsite with the BOP system; coupling the primary energy storage device to the electrically powered components to provide electric power for actuation of the electrically powered components; and maintaining a desired charge on the primary energy storage device via a secondary energy storage device which is nuclear powered.

18. The method as recited in claim 17, wherein providing comprises providing a subsea BOP system.

19. The method as recited in claim 18, further comprising locating the primary energy storage device and a secondary energy storage device proximate the BOP system at a subsea location.

20. The method as recited in claim 19, wherein providing the BOP system with electrically operated components comprises providing electric BOPs.

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