Electric safety valve modular compensation system

Abstract

A fluid pressure compensation system includes a housing, an electric actuator, a power spring, a stem, a stroking bellows, and a plurality of compensation bellows. The electric actuator is disposed in the housing. The power spring is disposed in the housing. The stem is operatively connected to the electric actuator and the power spring and slidably moveable relative to the housing. The stroking bellows is sealably connected to the housing and the stem. The plurality of compensation bellows is sealably connected to and extends laterally outwardly from the housing.

Description

ELECTRIC SAFETY VALVE MODULAR COMPENSATION SYSTEMCROSS-REFERENCES TO RELATED APPLICATIONS

[0001] This application claims priority to provisional application number 63 / 624,517 filed January 24, 2024.BACKGROUND

[0002] Safety valves are often used to quickly close hydrocarbon extraction wells. These safety valves often include internal components sealed in a housing to protect the internal components from the dirty surrounding downhole well environment. Devices to regulate pressure are often fluidly connected to manage pressure with the housing, but are susceptible to fouling with downhole debris. Consequently, these pressure-regulating devices are prone to malfunction and / or damage.SUMMARY

[0003] An electric downhole safety valves (eDHSV) is disclosed. The eDHSV is a subsurface safety valve and an emergency fail-safe flow controlling safety device that is configured to immediately shut in a well in case of emergency.

[0004] More specifically, a flapper of the eDHSV is electrically actuated. Further, the eDHSV is configured to close automatically when power is lost. The eDHSV includes an electric actuator, and electromagnetic coupling, and a power spring. The electromagnetic coupling makes a connection between the electric actuator and a flow tube, which opens and closes the flapper. The electric actuator converts electrical energy into linear motion to compress the power spring. If electrical power is lost, the electromagnetic coupling releases, the power spring pushes the flow tube out from under the flapper, and the flapper closes.

[0005] In one independent aspect, a fluid pressure compensation system includes a housing, an electric actuator, a power spring, a stem, a stroking bellows, and a plurality of compensation bellows. The electric actuator is disposed in the housing. The power spring is disposed in the housing. The stem is operatively connected to the electric actuator and the power spring and is slidably moveable relative to the housing. The stroking bellows is sealably connected to thehousing and the stem. The plurality of compensation bellows is sealably connected to and extends laterally outwardly from the housing.

[0006] In some embodiments, a flange of the stem is sealably connected to an end of the stroking bellows.

[0007] In some embodiments, the housing, the stroking bellows, and the plurality of compensation bellows are fdled with dielectric fluid.

[0008] In some embodiments, the stroking bellows and the plurality of compensation bellows are in fluid communication with the housing.

[0009] In some embodiments, the stroking bellows and each of plurality of the compensation bellows include a plurality of convolutions sealably connected to one another.

[0010] In some embodiments, each of the plurality of compensation bellows is shorter than the stroking bellows.

[0011] In some embodiments, the plurality of compensation bellows expands laterally outwardly from the housing when internal pressure in the housing increases.

[0012] In some embodiments, a first subset of the plurality of compensation bellows extends from a first side of the housing and a second subset of the plurality of compensation bellows extends from a second side of the housing.

[0013] In some embodiments, the plurality of compensation bellows extends orthogonally relative to a longitudinal axis of the housing.

[0014] In some embodiments, each of the plurality of compensation bellows is respectively disposed within one of a plurality of covers mounted to the housing.

[0015] In some embodiments, each of the plurality of compensation bellows is respectively seated in one of a plurality of outer recesses defined in the housing.

[0016] In some embodiments, the stroking bellows and each of the plurality of compensation bellows is configured to resiliently expand and contract.

[0017] In some embodiments, each of the plurality of compensation bellows includes a flanged base and an end cap.

[0018] In some embodiments, the power spring urges the stem toward a retracted position.

[0019] In some embodiments, each of the plurality of compensation bellows are in parallel fluid communication with one another.

[0020] In another independent aspect, an electric downhole safety valve includes an electronics section and a compensation system. The compensation system is operatively connected to the electronics section. The compensation system includes a stem, a housing, a stroking bellows, a plurality of compensation bellows, an electric actuator, and a power spring. The stem is slidably moveable relative to the housing. The stroking bellows is sealably connected to the stem and the housing. The plurality of compensation bellows is sealably connected to and laterally extends from the housing. The electric actuator and the power spring are operatively connected to the stem and sealed within a space defined by the housing, the stroking bellows, and the plurality of compensation bellows.

[0021] In some embodiments, a first subset of the plurality of compensation bellows extends from a first side of the housing and a second subset of the plurality of compensation bellows extends from a second side of the housing.

[0022] In some embodiments, each of the plurality of compensation bellows is respectively disposed in one of a plurality of covers mounted to the housing.

[0023] In a further independent aspect, a valve actuator includes a housing, a plurality of covers, a stroking bellows, a plurality of compensation bellows, a stem, an actuator, and a power spring. The plurality of covers is mounted to the housing. The stroking bellows is sealably connected to the housing. The plurality of compensation bellows is sealably connected to and laterally extends from the housing. Each of the plurality of compensation bellows is respectively slidably disposed in one of the plurality of covers. The stem is moveable relative to the housing and sealably connected to the stroking bellows. The housing, the stroking bellows, the plurality of compensation bellows, and the stem define a sealed interior space. The actuator is within the sealed interior space and is operatively connected to the stem. The power spring is within the sealed interior space and is operatively connected to the stem.

[0024] In some embodiments, the cover captures a flanged base of the compensation bellows against the housing.BRIEF DESCRIPTION OF THE DRAWINGS

[0025] The accompanying drawings, which are incorporated in and form a part of this specification, illustrate embodiments of the disclosure and, together with the description, serve to explain the principles of embodiments of the disclosure:

[0026] FIG. 1 is an isometric view of an electric downhole safety valve, according to an embodiment;

[0027] FIG. 2 is an isometric view of a compensation system of the electric downhole safety valve of FIG. 1;

[0028] FIG. 3 is side view of the compensation system of FIG. 2;

[0029] FIG. 4 is a cross-sectional view of a stroking bellows of the compensation system of FIG. 3;

[0030] FIG. 5 is a side view of a compensation bellows of the compensation system of FIG. 3;

[0031] FIG. 6 is a bottom isometric view of the compensation bellows of FIG. 5;

[0032] FIG. 7 is a partial isometric view of an electric downhole safety valve including compensation bellows housed within covers, according to another embodiment; and

[0033] FIG. 8 is a partial cross-sectional view of the electric downhole safety valve of FIG. 7.DETAILED DESCRIPTION

[0034] Various modifications to the illustrated embodiments will be readily apparent to those skilled in the art, and the generic principles herein can be applied to other embodiments and applications. Thus, it is to be understood that the disclosure is not limited in its application to the details of the configuration and arrangement of components set forth in the following description or illustrated in the accompanying drawings. The disclosure is capable of being practiced or of being carried out in various ways and is to be accorded the widest scope consistent with the principles and features disclosed herein. The following detailed description is to be read with reference to the figures, in which like elements in different figures have like reference numerals. The figures, which are not necessarily to scale, depict selected embodiments and are not intended to limit the scope of embodiments of the disclosure. Skilled artisans will recognize the examples provided herein have many useful alternatives and fall within the scope of the disclosure.

[0035] Before any embodiments are explained in detail, it is to be understood that the disclosure is not limited in its application to the details of construction and the arrangement of components set forth in the following description or illustrated in the attached drawings. The disclosure is capable of other embodiments and of being practiced or of being carried out in various ways. Also, it is to be understood that the phraseology and terminology used herein are for the purpose of description and should not be regarded as limiting. For example, the use of “including,”“comprising,” or “having” and variations thereof herein is meant to encompass the items listed thereafter and equivalents thereof as well as additional items.

[0036] As used herein, unless otherwise specified or limited, the terms “mounted,” “connected,” “supported,” and “coupled” and variations thereof are used broadly and encompass both direct and indirect mountings, connections, supports, and couplings. Further, unless otherwise specified or limited, “connected” and “coupled” are not restricted to physical or mechanical connections or couplings.

[0037] As used herein, unless otherwise specified or limited, “at least one of A, B, and C,” and similar other phrases, are meant to indicate A, or B, or C, or any combination of A, B, and / or C. As such, this phrase, and similar other phrases can include single or multiple instances of A, B, and / or C, and, in the case that any of A, B, and / or C indicates a category of elements, single or multiple instances of any of the elements of the categories A, B, and / or C.

[0038] As mentioned above, current devices and methods to form shoulders inside collars are inadequate and inefficient. Thus, it would be useful to provide more sophisticated and versatile devices and methods to form retaining shoulders for internal assemblies inside a collar.

[0039] In overview of the present teaching, this disclosure relates to pressure compensation systems for subsurface safety valves, which are emergency fail-safe flow-controlling safety devices. Subsurface safety valves are configured to immediately shut a well in case of emergency. In some instances, the subsurface safety valve is an electric downhole safety valve (eDHSV) in which a flapper is electrically actuated under normal operating conditions. In the event of an emergency and / or if electrical power to the eDHSV is lost, a power spring immediately mechanically actuates the flapper to a closed position.

[0040] More specifically, an electric actuator is operatively connected to the flapper and the power spring via an electromagnetic coupling. During normal operation, the electric actuator opens and closes the flapper and compresses the power spring. If electric power is lost, the electromagnetic coupling releases and the power spring extends to push the flapper to a closed position.

[0041] A compensation system may be used to seal the eDHSV to keeping internal components clean and protected from a surrounding dirty downhole environment and minimize differential pressure between an inside and an outside of the eDHSV. Thus, the electric actuator and the electromagnet of the eDHSV are sealed in clean chambers. More specifically, housingsthat contain a motor, gearbox, ball-screw, mechanical connecting components, the electromagnet, and wires are pre-filled with clean dielectric fluid (e.g., mineral oil, castor oil, silicone oil, etc.) to provide lubrication, rust prevention, etc. Vacuum filling is used to ensure all air is removed from the eDHSV and the housings are welded. Since the eDHSV actuates, metallic bellows are welded to the housings and to the output shaft. The bellows provide a flexible welded fluid barrier to keep the clean dielectric fluid in, and the dirty downhole fluid out of, precision actuation components of the eDHSV. Bellows sealing the output shaft and actuating housing are often referred to as stroking bellows.

[0042] A second flexible metallic bellows barrier is also attached to accommodate, absorb, and / or compensate for thermal and pressure effects on the dielectric fluid. For instance, when the eDHSV is installed, downhole temperatures are high and cause the dielectric fluid to thermally expand. The compensation bellows form a sealed chamber with an expandable volume that allows the dielectric fluid to expand freely. More specifically, the compensation bellows are attached to the actuating housing and are free to expand and retract based on fluid pressure inside the actuator housing. This ensures that pressure does not build up inside the actuator due to the fluid volume increasing by thermal expansion.

[0043] In some instances, the eDHSV must actuate rapidly to quickly retract the output shaft into the actuator housing. This rapid actuation in turn rapidly reduces the internal volume of the actuator housing, compressing the dielectric fluid and causing a pressure spike within the actuator housing, the stroking bellows, and the compensating bellows. If the bellows are impeded from freely expanding by downhole debris, then the eDHSV, particularly the bellows, may rupture due to pressure buildup. Improved bellows architecture of the disclosed eDHSV mitigates and / or reduces bellows rupture during quick actuations.

[0044] The disclosure utilizes multiple modular compensation bellows extending laterally from the actuation housing. The compensation bellows are thus fluidly in parallel with one another. In some instances, the compensation bellows are oriented perpendicularly to the actuation housing. Additionally, a stroking bellows is connected to and thus encloses the actuator housing and an output shaft, which moveably extends through the actuator housing. In some instances, the stroking bellows is longer than the compensation bellows.

[0045] Expansion of the stroking bellows is driven by actuation motion of the eDHSV. More specifically, motion of the output shaft relative to the actuator housing compresses and expandsconvolutions of the stroking bellows. In some instances, when the output shaft is in a fully retracted position, the installed stroking bellows is slightly stretched as compared to a relaxed state before the bellows are connected to the output shaft and the actuator housing. This slight stretching mitigates trapping debris between the convolutions, which may damage the stroking bellows.

[0046] The compensation bellows works to accommodate volume variations due to actuation of the output shaft and thermal expansion of the dielectric fluid. In some instances, the compensation bellows are housed in one or more external covers that provide guidance and a hard stop for expansion of the compensation bellows. In some instances, an internal filler feature at a cap of each bellows assembly acts to reduce oil volume inside the assembly and provides a hard stop for bellows retraction. Because the compensation bellows are fluidly arranged in parallel, an obstruction of a single compensation bellows does not obstruct the full compensation bellows assembly. Further, multiple flow channels facilitate flow of the dielectric fluid, making pressure compensation more responsive. Additionally, because the compensation bellows extend laterally from the actuator housing, debris accumulation is mitigated due to orientation perpendicular to gravity. Reduced length of the compensation bellows may mitigate squirm or buckling of the compensation bellows. Also, because the compensation bellows are relatively short, convolutions of the compensation bellows may be spaced further from one another, further mitigating downhole debris entrapment in the compensation bellows.

[0047] The disclosed compensation bellows are configured and / or shaped to be modular and thus usable with many different compensation systems. Thus, complexity and resultant cost of compensation systems may be reduced.

[0048] Referring generally to FIG. 1, a first example electric downhole safety valve (eDHSV) assembly 100 includes an electronics section 102 operatively connected to a compensation system 104. The compensation system 104 is filled with dielectric fluid (e.g., mineral oil, castor oil, silicone oil, etc.) to lubricate and provide corrosion protection to internal components. In some instances, during assembly, the compensation system 104 is vacuum filled to remove all air and completely fill the compensation system 104 with dielectric fluid. Thus, in some instances, the compensation system 104 is unitary and / or permanently sealed.

[0049] As shown in FIG. 2, the compensation system 104 includes an actuator housing 106 fluidly and sealably connected to a stroking bellows 108 and a plurality of compensation bellows 110. Thus, the actuator housing 106 acts as a manifold relative to the stroking bellows 108 andthe compensation bellows 110. A stem 1 12 is axially slidably moveable relative to the actuator housing 106 to extend and retract relative to the actuator housing 106. Further, the stem is sealably connected to the stroking bellows 108, which axially extends and retracts as the stem moves relative to the actuator housing 106. Thus, the actuator housing 106, the stroking bellows 108, the plurality of compensation bellows 110, and the stem 112 define a sealed interior space 114 (shown in FIG. 3).

[0050] In the illustrated example of FIG. 3, the actuator housing 106 is shown partially in phantom. The actuator housing 106 houses an electromagnet (not shown), an electric actuator 120 and a power spring 122, which are operatively connected to the stem 112. Further, the stroking bellows 108 is aligned and / or colinear with a longitudinal axis X of the actuator housing 106. A first subset 124 and a second subset 126 of the plurality of compensation bellows 110 extend from a first side 128 and a second side 130 of the actuator housing 106, respectively. The compensation bellows 110 of the first subset 124 are radially aligned with one another about the longitudinal axis X. Similarly, the compensation bellows 110 of the second subset 126 are radially aligned with one another about the longitudinal axis A. Additionally, in some instances, one or more of the plurality of compensation bellows 110 extend orthogonally from the actuator housing 106 relative to the longitudinal axis A. In some instances, the first subset 124 and the second subset 126 are arranged to be non-orthogonal and / or non-coplanar with one another about the longitudinal axis X. In some instances, the compensation bellows 110 are shorter than the stroking bellows 108.

[0051] With reference to FIG. 3, the stroking bellows 108 and the plurality of compensation bellows 110 are in fluid communication with the actuator housing 106 and with one another. Thus, the stroking bellows 108 and the plurality of compensation bellows 110 are in fluidly in parallel with one another via the actuator housing 106.

[0052] Remaining with FIG. 3, in operation, when the stem 112 (shown in FIG. 2) is actuated to retract into the actuator housing 106, the power spring 122 relaxes and the stroking bellows 108 contracts and thus pressurizes the internal dielectric fluid. Additionally in operation, as internal pressure of the dielectric fluid within the compensation system 104 increases, the compensation bellows 110 extend outwardly from the actuator housing 106. Thus, the compensation bellows 110 resiliently increase an internal volume of the compensation system 104 in response to and / or to compensate for increased internal fluid pressure. Consequently, in the event that the power spring 122 rapidly relaxes to quickly mechanically retract into the actuator housing 106, theplurality of compensation bellows 110 rapidly expand to absorb the resultant internal fluid pressure spike.

[0053] Referring again to FIG. 3, conversely, in operation, when the stem 112 (shown in FIG. 2) is actuated to extend from the actuator housing 106, the power spring 122 is energized to urge the stem 112 back to a retracted position and the stroking bellows 108 expands and thus depressurizes the internal dielectric fluid. Additionally in operation, as internal pressure of the dielectric fluid within the compensation system 104 decreases, the compensation bellows 110 retract inwardly toward the actuator housing 106. Thus, the compensation bellows 110 resiliently decrease an internal volume of the compensation system 104 in response to and / or to compensate for decreased internal fluid pressure.

[0054] With reference to FIG. 4, the stroking bellows 108 includes a plurality of convolutions 140 sealably connected to an end cap 142 and the stem 112 at a first end 144 and a second end 146, respectively (e.g., via welding). Each of the plurality of convolutions 140 are resiliently, flexibly, and sealably connected to one another (e.g., via welding). The end cap 142 is sealably connected to the actuator housing 106 and slidably engaged with the stem 112. The stem 112 is drivably connected to the electric actuator 120 and extends through the plurality of convolutions 140. A flange 148 of the stem 112 sealably connects to the second end 146 of the plurality of convolutions 140 (e.g., via welding).

[0055] With reference to FIGS. 5 and 6, each compensation bellows 110 includes a plurality of convolutions 160 sealably connected to a base 162 and an end cap 164 at a first end 166 and a second end 168, respectively (e.g., via welding). Each of the plurality of convolutions 160 are resiliently, flexibly, and sealably connected to one another (e.g., via welding). The base 162 includes a radially outwardly extending flange 170. As shown in FIG. 6, in some instances, the end cap 164 is internally threaded.

[0056] Turning to FIG. 7, a second example electric downhole safety valve (eDHSV) assembly 200 includes the plurality of compensation bellows 110 and a plurality of covers 202 extending from the actuator housing 106. More specifically, each of the compensation bellows 110 is respectively housed and extends within one of the covers 202. Each cover 202 is mounted to the actuator housing 106 via fasteners 204 (e.g., screws) extending through a mounting flange 206.

[0057] With reference to FIG. 8, in some instances, the flange 170 of the base 162 seats in an outer recess 220 defined in the actuator housing 106. Further, the cover 202 seats against theflange 170. Thus, the compensation bellows 1 10 is captured between the cover 202 and the actuator housing 106. The end cap 164 includes a stalk 222 that extends into an expansion chamber 224 defined by the plurality of convolutions 160. In some instances, the stalk 222 is internally threaded. The actuator housing 106 and the base 162 define a first port 226 and a second port 228, respectively. An internal chamber 230 of the actuator housing 106 is in fluid communication with the expansion chamber 224 via the first port 226 and the second port 228.

[0058] Remaining with FIG. 8, in operation, as pressure in the internal chamber 230 increases, the compensation bellows 110 expands until the end cap 164 encounters an end 240 of the cover 202. More specifically, the mounting flange 206 provides reaction forces against the flange 170. Conversely, as pressure in the internal chamber 230 decreases, the compensation bellows 110 retracts. Additionally, as the compensation bellows 110 expands and contracts, sides 242 of the cover 202 guide and align the end cap 164 and / or the plurality of convolutions 160.

[0059] In other embodiments, other configurations are possible. For example, those of skill in the art will recognize, according to the principles and concepts disclosed herein, that various combinations, sub-combinations, and substitutions of the components discussed above can provide improved compensation bellows systems.

[0060] The above description of the disclosed exemplary embodiments is provided to enable any person skilled in the art to make or use one or more aspects of the disclosure. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without departing from the spirit or scope of the disclosure. Thus, the disclosure is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

CLAIMSWhat is claimed is:

1. A fluid pressure compensation system comprising: a housing; an electric actuator disposed in the housing; a power spring disposed in the housing; a stem operatively connected to the electric actuator and the power spring and slidably moveable relative to the housing; a stroking bellows sealably connected to the housing and the stem; and a plurality of compensation bellows sealably connected to and extending laterally outwardly from the housing.

2. The fluid pressure compensation system of claim 1, wherein a flange of the stem is sealably connected to an end of the stroking bellows.

3. The fluid pressure compensation system of claim 1, wherein the housing, the stroking bellows, and the plurality of compensation bellows are filled with dielectric fluid.

4. The fluid pressure compensation system of claim 1, wherein the stroking bellows and the plurality of compensation bellows are in fluid communication with the housing.

5. The fluid pressure compensation system of claim 1, wherein the stroking bellows and each of the plurality of compensation bellows include a plurality of convolutions sealably connected to one another.

6. The fluid pressure compensation system of claim 1, wherein each of the plurality of compensation bellows is shorter than the stroking bellows.

7. The fluid pressure compensation system of claim 1 , wherein the plurality of compensation bellows expands laterally outwardly from the housing when internal pressure in the housing increases.

8. The fluid pressure compensation system of claim 1, wherein, a first subset of the plurality of compensation bellows extends from a first side of the housing and a second subset of the plurality of compensation bellows extends from a second side of the housing.

9. The fluid pressure compensation system of claim 1, wherein the plurality of compensation bellows extends orthogonally relative to a longitudinal axis of the housing.

10. The fluid pressure compensation system of claim 1, wherein each of the plurality of compensation bellows is respectively disposed within one of a plurality of covers mounted to the housing.

11. The fluid pressure compensation system of claim 1, wherein each of the plurality of compensation bellows is respectively seated in one of a plurality of outer recesses defined in the housing.

12. The fluid pressure compensation system of claim 1, wherein the stroking bellows and each of the plurality of compensation bellows is configured to resiliently expand and contract.

13. The fluid pressure compensation system of claim 1, wherein each of the plurality of compensation bellows includes a flanged base and an end cap.

14. The fluid pressure compensation system of claim 1, wherein the power spring urges the stem toward a retracted position.

15. The fluid pressure compensation system of claim 1, wherein each of the plurality of compensation bellows are in parallel fluid communication with one another.

16. An electric downhole safety valve comprising: an electronics section; and a compensation system operatively connected to the electronics section, the compensation system including a stem slidably moveable relative to a housing; a stroking bellows sealably connected to the stem and the housing; a plurality of compensation bellows sealably connected to and laterally extending from the housing; and an electric actuator and a power spring operatively connected to the stem and sealed within a space defined by the housing, the stroking bellows, and the plurality of compensation bellows.

17. The electric downhole safety valve of claim 16, wherein a first subset of the plurality of compensation bellows extends from a first side of the housing and a second subset of the plurality of compensation bellows extends from a second side of the housing.

18. The electric downhole safety valve of claim 16, wherein each of the plurality of compensation bellows is respectively disposed in one of a plurality of covers mounted to the housing.

19. A valve actuator comprising: a housing; a plurality of covers mounted to the housing; a stroking bellows sealably connected to the housing; a plurality of compensation bellows sealably connected to and laterally extending from the housing, each of the plurality of compensation bellows being respectively slidably disposed in one of the plurality of covers; a stem moveable relative to the housing and sealably connected to the stroking bellows and the housing, the stroking bellows, the plurality of compensation bellows, and the stem defining a sealed interior space; an actuator within the sealed interior space and operatively connected to the stem; anda power spring within the sealed interior space and operatively connected to the stem.

20. The valve actuator of claim 19, wherein the cover captures a flanged base of the compensation bellows against the housing.

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