Fail-safe safety cut-off valve for a fluid well

Abstract

A fail-safe sub-surface safety cut-off valve for fluid wells controllable from the surface and suitable for installation at substantially greater depths than prior constructions. The valve assembly is installable and retrievable via wire line technique and utilizes an electromagnetic means to operate either a flapper or a ball cut-off valve. The operating solenoid coil embraces a landing nipple portion of the tubing string and is outside the production flow. This solenoid supplies the power to open either type of cut-off valve and holds the latter open only so long as the solenoid is energized thereby providing surface control of the safety cut-off valve normally and assurance of closing of this valve in the event of power failure through accident or some catastrophe as well as automatic closure if flow velocity increases beyond a predetermined safe value.

We claim: 
     
       1. .[.A.]. .Iadd.That improvement in a fluid well tubing string which comprises: a .Iaddend.fail-safe safety cut-off valve.Iadd., .Iaddend..[.assembly suitable for use deeply submerged and supported coaxially of the tubing string of a fluid well comprising:.].  an open-ended tubular housing of non-magnetic material .[.forming a tubular portion of said tubing string and supporting a solenoid coil substantially embraced except on its interior side by magnetic material,.]. .Iadd.positioned between the opposite ends and forming part of said tubing string, a solenoid coil surrounding said tubular housing, .Iaddend.a tubular armature of magnetic material mounted within said housing and reciprocal between extended and retracted positions axially of said tubular housing and of said solenoid coil .[.and having cut-off valve means operatively associted therewith, spring means biasing said valve means closed and said armature to said extended position when said solenoid coil is de-energized, said solenoid coil, when energized, being effective to shift said armature to said retracted position and to open said cut-off valve, and means providing a fluid seal between the exterior of said armature and the interior of said tubular housing.]..Iadd., means positioned to engage and restrain axial movement of said armature when said armature reaches the retracted position thereof, cut-off valve means and valve seat means operatively associated with said tubular armature each within and independent of said tubular housing, said valve means, when open, being positioned out of the axial flow path of fluid through said cut-off valve, means biasing said valve means closed against said valve seat means and biasing said armature to said extended position when said solenoid coil is de-energized, said solenoid coil, when energized, being effective to shift said armature into engagement with said movement restraining means and to open said cut-off valve means, and means interconnecting and providing a fluid seal between said valve seat means and the interior of said tubular housing. .Iaddend. 
     
     
       2. .[.A valve assembly as.]. .Iadd.That improvement .Iaddend.defined in claim 1 characterized in .[.the provision of.]. .Iadd.that said movement restraining means for said armature includes a .Iaddend.tubular pole piece of magnetic material fixedly supported within .[.the tubular portion of the tubing string.]. .Iadd.said tubular housing .Iaddend.in alignment with said armature and providing a stop for the retracted position of said armature when said solenoid coil is energized. 
     
     
       3. .[.A valve assembly as.]. .Iadd.That improvement .Iaddend.defined in claim .[.1.]. .Iadd.2 .Iaddend.characterized in that said tubular pole piece is located .[.below the lower.]. .Iadd.adjacent one .Iaddend.end of said armature .[.and radially opposite the lower end of said armature.]. and radially opposite the .[.lower.]. .Iadd.contiguous .Iaddend.end of said .[.magnetic material embracing said.]. solenoid coil. 
     
     
       4. .[.A valve assembly as.]. .Iadd.That improvement .Iaddend.defined in claim .[.3.]. .Iadd.1 .Iaddend.characterized in that said valve means is .[.positioned adjacent the lower end of said armature and is.]. pivotable through approximately 90° about a generally horizontal axis. 
     
     
       5. .[.A valve assembly as.]. .Iadd.That improvement .Iaddend.defined in claim 4 characterized in the provision of means for .Iadd.movably .Iaddend.supporting said valve means .[.on said valve assembly.]. .Iadd.within said tubular housing .Iaddend.independently of said armature. 
     
     
       6. .[.A valve assembly as.]. .Iadd.That improvement .Iaddend.defined in claim 4 characterized in the provision of means movably supporting said valve means between the opposite ends of said armature .Iadd.when in said retracted position thereof .Iaddend.for pivotal movement about an axis extending transversely of said armature. 
     
     
       7. .[.A valve assembly as.]. .Iadd.That improvement .Iaddend.defined in claim 4 characterized in that said valve means comprises a ball having a flow passage diametrically therethrough, and means operatively connected to said ball for rotating said ball through a 90° arc between the closed and open positions thereof as said armature is moved from its .[.upper.]. extended position .[.and.]. .Iadd.to .Iaddend.its .[.lower closed.]. .Iadd.retracted .Iaddend.position in response to energization of said solenoid coil. 
     
     
       8. .[.A valve assembly as.]. .Iadd.That improvement .Iaddend.defined in claim 7 characterized in that said armature includes axially aligned upper and lower portions the adjacent ends of which are disposed opposite upper and lower surfaces of said .[.sphere.]. .Iadd.ball. .Iaddend. 
     
     
       9. .[.A.]. .Iadd.That improvement in a fluid well tubing string which comprises: a .Iaddend.fail-safe safety cut-off valve .[.assembly.]. for sub-surface installation along a .Iadd.non-magnetic .Iaddend.section of .[.a fluid well.]. .Iadd.said .Iaddend.tubing string, .[.formed of non-magnetic material.].  a solenoid coil .[.wound about the exterior of.]. .Iadd.encircling .Iaddend.said non-magnetic section.Iadd., .Iaddend..[.encased on its exterior and ends by thick-walled magnetic material.].  a tubular armature of magnetic material reciprocally supported within and lengthwise of said non-magnetic section .[.of said tubing string and including means providing a fluid-tight seal between the exterior of said armature and the interior of said non-magnetic section of said tubing string, a tubular pole piece of magnetic material fixed to said non-magnetic section radially inwardly of the lower end of said solenoid coil and adjacent to and aligned with the lower end of said armature, valve means adjacent the lower end of said armature movable between open and closed positions to control flow through said armature, spring means urging said armature to the elevated extended position thereof spaced above said pole piece with said valve means closed when said coil is de-energized, and said coil being operable when energized to move said armature axially toward said pole piece and to hold said valve means open so long as said coil remains energized.]., .Iadd.tubular pole piece means of magnetic material within said non-magnetic section radially inwardly of one end of said solenoid coil and adjacent to and aligned with the contiguous end of said armature and including valve seat means supported crosswise of said non-magnetic section, spring-biased valve means movable between open and closed positions relative to said valve seat means to control flow through said armature, spring means biasing said armature to the extended position thereof spaced from said pole piece with said valve means closed when said coil is de-energized, and said solenoid coil being operable when energized to move said armature axially toward said pole piece and to hold said valve means open. .Iaddend. 
     
     
       10. .[.A valve assembly as.]. .Iadd.That improvement .Iaddend.defined in claim 9 characterized in the provision of a tubular housing of non-magnetic material embracing said armature, said tubular pole piece, said spring means and said valve means and holding the same operatively assembled to one another as a unitary sub-assembly, and separable coupling means carried in part by said non-magnetic section and in part by said .Iadd.unitary .Iaddend.sub-assembly for holding said .Iadd.unitary .Iaddend.sub-assembly detachably connected to said non-magnetic section of said flow tube. 
     
     
       11. .[.A valve assembly as.]. .Iadd.That improvement .Iaddend.defined in claim 9 characterized in the provision of electrical leads for said solenoid coil which extend between the entrance to .[.the oil.]. .Iadd.said fluid .Iaddend.well and said coil along the exterior of said tubing string. 
     
     
       12. .[.A valve assembly as.]. .Iadd.That improvement .Iaddend.defined in claim 9 characterized in that said valve means comprises a flapper valve pivoted to .[.one of said non-magnetic tubes in an area.]. .Iadd.said valve seat means .Iaddend.along one lateral side of the .[.lower.]. .Iadd.contiguous .Iaddend.end of said armature. 
     
     
       13. .[.A valve assembly as.]. .Iadd.That improvement .Iaddend.defined in claim .[.9.]. .Iadd.18 .Iaddend.characterized in that said valve means comprises a ball rotatably supported crosswise of said armature and having a flow passage diametrically thereof, and means for rotating said ball about a horizontal axis between open and closed position as said armature reciprocates between the extended and retracted positions thereof upon energization of said solenoid coil. 
     
     
       14. .[.A valve assembly as.]. .Iadd.That improvement .Iaddend.defined in claim 10 characterized in the provision of electrical leads extending from said .Iadd.solenoid .Iaddend.coil to the well head along the exterior of said tubing string, and said .Iadd.solenoid .Iaddend.coil being effective to hold said .Iadd.spring-biased .Iaddend.valve means open .[.in opposition to said spring means.]. only so long as said coil remains energized. 
     
     
       15. .[.A valve assembly as.]. .Iadd.That improvement .Iaddend.defined in claim 1 characterized in that said solenoid coil is effective to hold said tubular armature in position to hold said .[.cut-off.]. valve means in open position until the flow velocity through said tubular armature and the resulting friction losses increase beyond a predetermined value exceeding the magnetic holding power of said solenoid coil whereupon said .[.spring.]. .Iadd.valve .Iaddend.means .[.is effective to close said cut-off valve.]. .Iadd. closes.Iaddend.. 
     
     
       16. .[.A valve assembly as.]. .Iadd.That improvement .Iaddend.defined in claim .[.15.]. .Iadd.9 .Iaddend.characterized in the provision of means remote from said cut-off valve for varying the voltage applied to said solenoid coil for varying the holding power of said solenoid coil. 
     
     
       17. .[.A valve assembly as.]. .Iadd.That improvement .Iaddend.defined in claim 15 characterized in the provision of means remote from said cut-off valve to adjust the voltage.[.s.]. applied to said solenoid coil to energize the same thereby to adjust the holding power of said coil on said tubular armature and whereby said .[.cut-off.]. valve .Iadd.means .Iaddend.will automatically close when the pressure differential across said .[.cut-off.]. valve .Iadd.means .Iaddend.reaches a different predetermined value. .Iadd. 18. A fail-safe safety cut-off valve for a fluid well tubing string comprising: a tubular housing insertable between the adjacent ends of contiguous sections of a conventional tubing string, a cut-off valve sub-assembly embraced by and mounted within said tubular housing and including coupling means interiorly of said tubular housing holding said valve sub-assembly detachably coupled as a unit to said tubular housing and, when uncoupled, permitting withdrawal of said valve sub-assembly as a unit through a tubing string, said valve sub-assembly including valve seat means and pivoting valve means biased toward closed position thereagainst, solenoid means for opening and retaining said valve means open comprising tubular armature means mounted within and reciprocal axially of said housing between an extended position wherein said valve means is closed on said valve seat means and a retracted position wherein said valve means is held open, means for shifting said armature means to said extended position, and solenoid coil means operable when energized to shift said armature means to said retracted position to open and retain said valve means in open position. .Iaddend. .Iadd. 19. A cut-off valve as defined in claim 18 characterized in that said solenoid coil means encircles said tubular housing along portions thereof to either axial side of said valve means. .Iaddend..Iadd.  20. A cut-off valve as defined in claim 18 characterized in that said means for shifting said armature means to the extended position thereof comprises spring means. .Iaddend..Iadd. 21. A cut-off valve as defined in claim 18 characterized in the provision of tubular pole-piece means of magnetic material spaced axially from the flow inlet to said valve seat means with the one end of said tubular pole-piece means positioned to engage and provide a stop for the adjacent end of said armature means when said solenoid coil means is energized. .Iaddend..Iadd. 22. A cut-off valve as defined in claim 18 characterized in that said cut-off valve sub-assembly includes means located interiorly of said tubular housing for detachably coupling said cut-off valve sub-assembly to said tubular housing thereby to permit installation and removal of said sub-assembly as a unit through an installed tubing string. .Iaddend..Iadd. 23. A cut-off valve as defined in claim 18 characterized in that said valve means comprises a flapper valve pivotally supported near one edge of said valve seat means. .Iaddend..Iadd. 24. A cut-off valve as defined in claim 18 characterized in that said tubular armature means is reciprocal through said valve seat means while moving between the extended and retracted positions thereof and is effective to isolate said valve seat means from contact with flowing well fluid while holding said valve means open. .Iaddend. .Iadd. 25. A cut-off valve as defined in claim 23 characterized in that said flapper valve is supported exteriorly of said tubular armature means so long as said armature means is in the retracted position thereof. .Iaddend..Iadd. 26. A cut-off valve as defined in claim 21 characterized in that said valve means is movably supported between said valve seat means and said pole piece means and is movable to an open position along one exterior side of said tubular armature means so long as one end of said armature means engages the adjacent end of said pole piece means. .Iaddend..Iadd. 27. A cut-off valve as defined in claim 25 characterized in that said valve means comprises a flapper valve pivotable between a closed position transversely of said tubing string and and open position lengthwise of said tubing string and along the exterior of said armature means. .Iaddend..Iadd. 28. A cut-off valve as defined in claim 21 characterized in that said armature means is reciprocal through said valve seat means into engagement with said pole piece means when said solenoid means is energized and is operable to open said valve means to a position exteriorly of said armature means while moving toward said pole piece means. .Iaddend..Iadd. 29. A cut-off valve as defined in claim 27 characterized in that said tubular armature means cooperates with said pole piece means when engaged therewith to isolate said valve means and said valve seat means from flowing well fluid. .Iaddend. .Iadd. 30. A cut-off valve as defined in claim 21 characterized in that said tubular pole piece means and said tubular armature means cooperate in the retracted position of said armature means to provide an unobstructed tubular flow passage past said valve means. .Iaddend..Iadd. 31. A cut-off valve as defined in claim 29 characterized in that said valve means and said valve seat means are isolated from flowing well fluid when said solenoid means is energized to hold said armature means retracted, and said armature means being operable while moving to the retracted position thereof to open said valve means. .Iaddend..Iadd. 32. A fail-safe safety cut-off valve for a fluid well comprising: a landing nipple insertable between the adjacent ends of contiguous sections of a tubing string, a cut-off valve sub-assembly embraced by said landing nipple, separable coupling means manipulatable from the interior of said sub-assembly while said safety cut-off valve is installed in a tubing string thereby detachably supporting said valve sub-assembly within said landing nipple for withdrawal therefrom through an installed tubing string, said valve sub-assembly including valve seat means and pivoting valve means biased toward closed position against said valve seat means, tubular armature means reciprocally supported within and lengthwise of said landing nipple normally spring-biased to the extended position thereof, and including means operable to open said valve means while moving to the retracted position thereof, solenoid means carried by said landing nipple and operable when energized to move said armature means to the retracted position thereof and to hold said valve means open. .Iaddend. .Iadd. 33. A safety cut-off valve as defined in claim 32 characterized in the provision of readily separable coupling means for holding said cut-off valve sub-assembly detachably assembled to the interior of said landing nipple. .Iaddend..Iadd. 34. That improvement defined in claim 1 characterized in that said valve means comprises a ball having a diametric flow passage therethrough, and means operatively connected to said ball for rotating said ball between closed and open positions in response to movement of said armature from its extended position to its restrained retracted position upon energization of said solenoid coil. .Iaddend..Iadd. 35. A fail-safe safety cut-off valve for a fluid well comprising: a tubular housing insertable between the adjacent ends of contiguous sections of a conventional tubing string, a cut-off valve sub-assembly embraced by and mounted within said tubular housing including valve seat means and pivoting valve means biased toward closed position thereagainst, said cut-off valve sub-assembly including means for holding the same detachably coupled to said tubular housing for installation therein and withdrawal therefrom while said tubular housing remains assembled between the opposite ends of a tubing string, solenoid means for opening and retaining said valve means open comprising tubular armature means mounted within and reciprocal axially of said housing between an extended position wherein said valve means is closed on said valve seat means and a retracted position wherein said valve means is held open, means for shifting said armature means into engagement with armature movement restraining means when said solenoid means is energized, and solenoid coil means operable when energized to shift said armature means to said retracted position to open and retain said valve means in open position. .Iaddend. .Iadd. 36. A safety cut-off valve as defined in claim 35 characterized in that said tubular housing is imperforate and without electrical conductors passing therethrough. .Iaddend..Iadd. 37. A safety cut-off valve as defined in claim 36 characterized in that said valve means includes a ball having a fluid flow passage therethrough and including means for pivoting said ball between the open and closed positions thereof as said tubular armature means moves away from the retracted to the extended position thereof. .Iaddend..Iadd. 38. That improvement in a fluid well tubing string which comprises: a fail-safe safety cut-off valve, an open-ended tubular housing of non-magnetic material positioned between the opposite ends and forming part of said tubing string, a solenoid coil surrounding said tubular housing, a tubular armature of magnetic material mounted within said housing and reciprocal between extended and retracted positions axially of said tubular housing and of said solenoid coil, cut-off valve means and valve seat means operatively associated with said tubular armature and one of which means is movably supported independently of said armature, means biasing said valve means closed against said valve seat means and biasing said armature to said extended position when said solenoid coil is de-energized, said solenoid coil, when energized, being effective to shift said armature to said retracted position and to open said cut-off valve means, and means interconnecting and providing a fluid seal between said valve seat means and the interior of said tubular housing. .Iaddend.