Electric safety valve compensation system

Abstract

A compensation system may comprise an actuator sealed in a chamber. The chamber may comprise an actuator rod and a first bellow, wherein expansion of the first bellow is configured to extend the first bellow into a first cavity in the chamber, which moves the actuator rod towards the first cavity. The chamber may comprise a second bellow, wherein expansion of the second bellow is configured to extend the second bellow into a second cavity in the chamber. The first cavity is configured to be filled with dielectric fluid, the dielectric fluid moving between the first cavity and the second bellow based on a displacement caused by a movement of the actuator rod.

Description

ELECTRIC SAFETY VALVE COMPENSATION SYSTEMCROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims the priority benefit of United States Provisional Application No. 63 / 516,888 filed August 1, 2023, the entire contents of which are hereby incorporated by reference.BACKGROUND

[0002] The present disclosure generally relates to safety valves, and more particularly to safety valves having electrical actuators and fully electric safety valves. The subsurface safety valve is an emergency fail-safe flow controlling safety device that is used to immediately shut in a well in case of emergency. The subsurface safety valve’s key mission is to close immediately in an emergency to protect lives and the environment.

[0003] In electric safety valves, electricity is used to actuate a flapper. The electric safety valve must close automatically when power is lost. When power is lost, the flapper will close creating a barrier to prevent fluid from traveling up a tubing.SUMMARY

[0004] In general, a methodology and system are provided for a compensation system for use, for example, in an electric safety valve assembly. The electric safety valve assembly may include a flapper, a return spring, an internal tubing sleeve and an actuator. The actuator is an electric actuator with an electro-magnet coupling and the power spring. The electromagnet coupling makes a connection between the actuator and the flow tube. The electric actuator converts electricity into linear motion to compress the power spring. When power is lost, the electro-magnet coupling releases and the power spring then pushes the flow tube and uncovers the flapper. Once the flapper is uncovered, the flapper closes and the flapper closes. There is a need to actuate the flapper faster, without rupturing the compensation system.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.

[0006] FIG. 1 is compensation system with bellows for an electric safety valve.

[0007] FIG. 2 illustrates the dielectric fluid path from one bellow to another bellow during actuation.

[0008] FIG. 3 illustrates an obstruction during actuation causing a rupture.

[0009] FIG. 4 illustrates a compensation system for an actuator with a piston and fluid passage as the third fluid barrier, according to one or more embodiments of the present disclosure.

[0010] FIG. 5 illustrates a compensation system for an actuator with a third bellow as the third fluid barrier, according to one or more embodiments of the present disclosure.DETAILED DESCRIPTION

[0011] In the following description, numerous details are set forth to provide an understanding of some embodiments of the present disclosure. It is to be understood that the following disclosure provides many different embodiments, or examples, for implementing different features of various embodiments. Specific examples of components and arrangements are described below to simplify the disclosure. These are, of course, merely examples and are not intended to be limiting. 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 thedescribed embodiments are possible. This description is not to be taken in a limiting sense, but rather made merely for the purpose of describing general principles of the implementations. The scope of the described implementations should be ascertained with reference to the issued claims.

[0012] As used herein, the terms “connect”, “connection”, “connected”, “in connection with”, and “connecting” are used to mean “in direct connection with” or “in connection with via one or more elements”; and the term “set” is used to mean “one element” or “more than one element”. Further, the terms “couple”, “coupling”, “coupled”, “coupled together”, and “coupled with” are used to mean “directly coupled together” or “coupled together via one or more elements”. As used herein, the terms "up" and "down"; "upper" and "lower"; "top" and "bottom"; and other like terms indicating relative positions to a given point or element are utilized to more clearly describe some elements. Commonly, these terms relate to a reference point at the surface from which drilling operations are initiated as being the top point and the total depth being the lowest point, wherein the well (e.g., wellbore, borehole) is vertical, horizontal or slanted relative to the surface.

[0013] The electric actuator and electro-magnet of an electric safety valve are sealed in a chamber to protect the components from the dirty downhole environment. The chamber is filled with dielectric fluid. The chamber may comprise one or more bellows (e.g., bellows, pistons, fluid barrier, fluid actuator, fluid reservoir) utilized to act as a fluid barrier between the dielectric fluid and the downhole fluid. A second bellow is also attached to “compensate” for thermal and pressure affects on the dielectric fluid. For instance, when the valve is installed downhole the temperatures are high and this will cause the dielectric fluid to thermally expand. The one or more compensation bellows allow for the dielectric fluid to expand freely. The one or more bellows may cause the sealed chamber to have an expandable volume - this ensures that pressure does not build up inside the actuator due to the increasing fluid volume due to thermal expansion.

[0014] FIG. 1 illustrates an arrangement of two bellows, a stroking bellow (e.g., actuator rod with a piston) and a compensation bellow (e.g., actuator rod with a piston). Thecompensation system of FIG. 1 may comprise one or more (e.g., 1, 2, 3, 4, 5, 6, 7, 8, etc.) stroking bellows 102, one or more (e.g., 1, 2, 3, 4, 5, 6, 7, 8, etc.) compensation bellows 104, one or more filled volumes 106, and one or more filled volumes 108.

[0015] FIG. 2 illustrates the dielectric fluid path from one bellow to another bellow. Compensation system 200 may comprise a stroking bellow 202 and a compensation bellow 204. As the stroking bellow 202 extends, the fluid (e.g., oil) in the cavity may be displaced into the compensation bellow 204, thus causing the compensation bellow 204 to expand. In compensation system 210, the stroking bellow 202 and the compensation bellow 204 may be extended due to the fluid from outside the stroking bellows going into the compensation bellow 204.

[0016] FIG. 3 illustrates compensation 300 with a rupture 314, when debris impedes the one or more bellows (e.g., stroking bellow 302, compensation bellow 304). During a quick actuation the fluid may need to move quickly and any restriction in flow may create a spike of pressure that could rupture the one or more bellows. A rod may attempt to quickly actuate but be blocked by debris 312.

[0017] Figs. 4 and 5 illustrate a novel feature to reduce the possibility of a rupture of the one or more bellows.

[0018] FIG. 4 illustrates a compensation system 400 for an actuator with a piston (e.g., third fluid barrier) 416 and fluid passage as the third fluid barrier. The third fluid barrier 416. A pressure conduit 418 may allow pressure to move from stroking bellow 402 to compensation bellow 404. The pressure conduit 418 may be positioned between the stroking bellow 402 to compensation bellow 404. In the case of a blockage, the third barrier 416 does not need to move because the dielectric fluid may move from the stroking bellow 402 and compensation bellow 404 via the pressure conduit 418.

[0019] FIG. 5 illustrates a compensation system 500 for an actuator with a third bellow as the third fluid barrier.

[0020] At least one embodiment utilizes two bellows of similar diameter. The bellows may have similar volume when expanding and contracting. A third fluid barrier may then be added to enclose the two bellows with dielectric fluid on the inside of the system. This third barrier could comprise a third bellow and / or a piston with seal. Since the first two bellows are of similar volume, the fluid on the outside of the two bellows can be passed back and forth as the system extends / retracts. For instance, when one bellow expands, the volume in the cavity outside of bellow will decrease. The fluid that was in the cavity outside of a below then can pass through a passage to the cavity of the other bellows.

[0021] The key benefit of this technology is that the third fluid barrier (e.g. piston or bellow) does not need to move due to actuation. This will significantly improve performance in downhole dirty environments since the bellows do not need to push quickly through solid or asphaltenes.

[0022] The third barrier illustrated above is a piston as illustrated in FIG. 4. The piston is enclosed with dielectric fluid around the two bellows and a fluid passage to allow fluid to move from one bellow to another.

[0023] The third barrier illustrated above is a bellow as illustrated in FIG. 5. The striking bellow 502 and the compensation bellow 504 may be enclosed with dielectric fluid and a fluid passage (e.g., pressure conduit) 518 to allow fluid to move from one bellow to another. The third barrier 520 (e.g., piston, bellow) may not move substantially because the dielectric fluid may move from (e.g., between) the striking bellow 502 and the compensation bellow 504.

[0024] The third barrier (e.g., piston and / or bellow) does need to move to compensate temperature and pressure effects on the dielectric fluid. However, this movement occurs much slower than a safety valve slam closure and the temperature at the safety valve is stable over long periods of time so the third barrier will remain relatively static for long periods of time through most of the life of the safety valve.

[0025] 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

CLAIMS1. A compensation system comprising: an actuator sealed in a chamber, the chamber comprising: an actuator rod and a first bellow, wherein expansion of the first bellow is configured to extend the first bellow into a first cavity in the chamber, which moves the actuator rod towards the first cavity; a second bellow, wherein expansion of the second bellow is configured to extend the second bellow into a second cavity in the chamber; and wherein the first cavity is configured to be filled with dielectric fluid, the dielectric fluid moving between the first cavity and the second bellow based on a displacement caused by a movement of the actuator rod.

2. The compensation system of claim 1, further comprising a third bellow in the second cavity.

3. The compensation system of claim 2, further comprising a pressure conduit fluidically connecting the first cavity to the third bellow.

4. The compensation system of claim 3, wherein the movement of the actuator rod displaces the dielectric fluid to the third bellow via the pressure conduit.

5. The compensation system of claim 2, wherein the third bellow is configured to be static.

6. The compensation system of claim 1, further comprising a return spring configured to bias the actuator rod towards the first cavity.

7. The compensation system of claim 6, further comprising an electromagnetic coupling forming a magnetic connection with the actuator rod, wherein the actuator rod is configured to compress the return spring when the electromagnetic coupling is powered.

8. The compensation system of claim 7, further comprising a third bellow in the second cavity.

9. The compensation system of claim 8, further comprising a pressure conduit fluidically connecting the first cavity to the second cavity.

10. The compensation system of claim 9, wherein the movement of the actuator rod is configured to displace and move the dielectric fluid to the third bellow via the pressure conduit.

11. The compensation system of claim 1, further comprising a flapper actuated by the actuator.

12. A method for operating a compensation system, the method comprising: triggering expansion of a first bellow in a chamber of an actuator, which moves an actuator rod into a first cavity in the chamber; and moving dielectric fluid filling the chamber by the movement of the actuator rod to a second bellow, expanding the second bellow which extends into a second cavity in the chamber.

13. The method of claim 12, further comprising moving the dielectric fluid filling the chamber via the actuator rod to a third bellow via a pressure conduit.

14. The method of claim 13, wherein the third bellow is static.

15. The method of claim 11, further comprising biasing the actuator rod towards the first cavity via a return spring.

16. The method of claim 15, wherein an electromagnetic coupling forms a magnetic connection with the actuator rod, the actuator rod compressing the return spring when the electromagnetic coupling is powered.

17. The method of claim 16, further comprising moving the dielectric fluid fdling the chamber by the actuator rod to a third bellow via a pressure conduit.

18. The method of claim 17, further comprising moving the dielectric fluid fdling the chamber by the actuator rod to a third bellow via a pressure conduit.

19. The method of claim 14, wherein the compensation system further comprises a flapper actuated by the actuator.

20. The method of claim 18, wherein the compensation system further comprises a flapper actuated by the actuator.

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