IPC분류정보
국가/구분 |
United States(US) Patent
등록
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국제특허분류(IPC7판) |
|
출원번호 |
US-0348397
(2003-01-21)
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발명자
/ 주소 |
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출원인 / 주소 |
- Baker Hughes Incorporated
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인용정보 |
피인용 횟수 :
9 인용 특허 :
14 |
초록
▼
An improved control system, particularly useful for SSVs, is disclosed. It is responsive to a rupture of the tubing and control line to equalize pressure on an operating piston to allow the SSV to go to its failsafe position. The annulus pressure-sensing feature can be employed with a variety of con
An improved control system, particularly useful for SSVs, is disclosed. It is responsive to a rupture of the tubing and control line to equalize pressure on an operating piston to allow the SSV to go to its failsafe position. The annulus pressure-sensing feature can be employed with a variety of control systems, a particular one is used as an example.
대표청구항
▼
1. A control system for a tubing mounted downhole safety valve operated from the surface, comprising:a fluid filled control line extending in an annular space outside the tubing from the surface and in fluid communication with a first end of an operating piston; a return spring acting on said piston
1. A control system for a tubing mounted downhole safety valve operated from the surface, comprising:a fluid filled control line extending in an annular space outside the tubing from the surface and in fluid communication with a first end of an operating piston; a return spring acting on said piston in a direction against hydrostatic pressure from said fluid filled control line but being weaker than the hydrostatic force exerted by said fluid filled control line; a pressure source acting on a second end of said operating piston against the hydrostatic force from said control line, said pressure source further comprising a valve to selectively communicate annular space pressure to said second end of said piston. 2. The control system of claim 1, wherein:said valve operates responsively to pressure in the annular space. 3. The control system of claim 2, wherein:said valve opens when annular space pressure rises to exceed a predetermined pressure source value. 4. The control system of claim 3, wherein:said valve opens to put said piston in pressure balance from annular space pressure. 5. The control system of claim 4, wherein:said first end of said piston is exposed to annular space pressure as a result of a break in said control line. 6. The control system of claim 5, wherein:said break in said control line results from a failure of the tubing on which the safety valve is mounted with a resulting pressurization of the annular space from pressure formerly within the tubing. 7. The control system of claim 1, wherein:said pressure source comprises a fluid filled balance line extending from said second end of said piston to the surface. 8. The control system of claim 1, wherein:said valve opens when annular space pressure rises to exceed a predetermined pressure source value. 9. The control system of claim 1, wherein:said valve opens to put said piston in pressure balance from annular space pressure. 10. The control system of claim 1, wherein:said first end of said piston is exposed to annular space pressure as a result of a break in said control line. 11. The control system of claim 10, wherein:said break in said control line results from a failure of the tubing on which the safety valve is mounted with a resulting pressurization of the annular space from pressure formerly within the tubing. 12. A control system for a tubing mounted downhole safety valve operated from the surface, comprising:a fluid filled control line extending in an annular space outside the tubing from the surface and in fluid communication with a first end of an operating piston; a return spring acting on said piston in a direction against hydrostatic pressure from said fluid filled control line but being weaker than the hydrostatic force exerted by said fluid filled control line; a pressure source acting on a second end of said operating piston against the hydrostatic force from said control line, said pressure source further comprising a valve to selectively communicate annular space pressure to said second end of said piston; said pressure source comprises a pressurized reservoir mounted adjacent said piston. 13. A control system for a tubing mounted downhole safety valve operated from the surface, comprising:a fluid filled control line extending in an annular space outside the tubing from the surface and in fluid communication with a first end of an operating piston; a return spring acting on said piston in a direction against hydrostatic pressure from said fluid filled control line but being weaker than the hydrostatic force exerted by said fluid filled control line; a pressure source acting on a second end of said operating piston against the hydrostatic force from said control line, said pressure source further comprising a valve to selectively communicate annular space pressure to said second end of said piston; said valve operates responsively to pressure in the annular space; said valve opens when annular space pressure rises to exceed a predetermined pressure source value; said valve opens to put said piston in pressure balance from annular space pressure, said first end of said piston is exposed to annular space pressure as a result of a break in said control line, said break in said control line results from a failure of the tubing on which the safety valve is mounted with a resulting pressurization of the annular space from pressure formerly within the tubing; said pressure source comprises a pressurized reservoir mounted adjacent said piston. 14. The control system of claim 13, wherein:said valve comprises a valve member having a first diameter and movable in a housing having a larger second diameter such that movement of said valve member due to an increase in annular space pressure creates a bypass passage around said valve member to allow annular space pressure to reach said second end of said piston. 15. The control system of claim 13, wherein:said valve comprises a valve member in a housing having a unidirectional seal such that annular space pressure, when greater than the pressure source pressure, creates blow-by past said seal. 16. The control system of claim 13, wherein:said valve comprises a check valve allowing flow in one direction from the annular space to said second end of said piston. 17. A control system for a tubing mounted downhole safety valve operated from the surface, comprising:a fluid filled control line extending in an annular space outside the tubing from the surface and in fluid communication with a first end of an operating piston; a return spring acting on said piston in a direction against hydrostatic pressure from said fluid filled control line but being weaker than the hydrostatic force exerted by said fluid filled control line; a pressure source acting on a second end of said operating piston against the hydrostatic force from said control line, said pressure source further comprising a valve to selectively communicate annular space pressure to said second end of said piston; said valve comprises a valve member having a first diameter and movable in a housing having a larger second diameter such that movement of said valve member due to an increase in annular space pressure creates a bypass passage around said valve member to allow annular space pressure to reach said second end of said piston. 18. A control system for a tubing mounted downhole safety valve operated from the surface, comprising:a fluid filled control line extending in an annular space outside the tubing from the surface and in fluid communication with a first end of an operating piston; a return spring acting on said piston in a direction against hydrostatic pressure from said fluid filled control line but being weaker than the hydrostatic force exerted by said fluid filled control line; a pressure source acting on a second end of said operating piston against the hydrostatic force from said control line, said pressure source further comprising a valve to selectively communicate annular space pressure to said second end of said piston; said valve comprises a valve member in a housing having a unidirectional seal such that annular space pressure, when greater than the pressure source pressure, creates blow-by past said seal. 19. A control system for a tubing mounted downhole safety valve operated from the surface, comprising:a fluid filled control line extending in an annular space outside the tubing from the surface and in fluid communication with a first end of an operating piston; a return spring acting on said piston in a direction against hydrostatic pressure from said fluid filled control line but being weaker than the hydrostatic force exerted by said fluid filled control line; a pressure source acting on a second end of said operating piston against the hydrostatic force from said control line, said pressure source further comprising a valve to selectively communicate annular space pressure to said second end of said piston; said valve comprises a check valve allowing flow in one direction from the annular space to said second end of said piston. 20. A method of obtaining a failsafe operation for a downhole safety valve, comprising:running a control line in an annular space to one end of an operating piston on a safety valve mounted on tubing; providing a pressure source on an opposed end of said operating piston to counteract hydrostatic pressure on said operating piston; providing a return spring on said operating piston that is weaker than the opposing hydrostatic force on said one end of said piston from said control line; responding to an annular space pressure rise coupled with breakage of said control line, while said pressure source remains intact, by equalizing annular space pressure on opposed ends of said piston.
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