초록 ▼

A well choke, and an actuation mechanism for the well choke are described. The actuation mechanism includes a linearly translating drive mechanism which is coupled to a valve member drive assembly through a fluid coupling which facilitates a change in the overall length of the actuation mechanism. F

A well choke, and an actuation mechanism for the well choke are described. The actuation mechanism includes a linearly translating drive mechanism which is coupled to a valve member drive assembly through a fluid coupling which facilitates a change in the overall length of the actuation mechanism. Fluid in the fluid coupling can be released in response to fluid pressure exerted on the valve member when it is proximate a valve seat of the choke, to achieve this change in length. In some embodiments, the fluid coupling will provide a retained fluid column and the valve member drive assembly will include a piston with in the fluid coupling which is movable from a fully extended to a compressed, by the release of fluid from the coupling in response to pressure in the chamber reaching a threshold level.

대표청구항 ▼

1. A well fluid flow control device, comprising: a valve housing assembly including a valve seat;a valve closure member at least partially within the valve housing assembly and selectively moveable relative to the valve seat; andan actuation mechanism coupled to the valve closure member and operable

1. A well fluid flow control device, comprising: a valve housing assembly including a valve seat;a valve closure member at least partially within the valve housing assembly and selectively moveable relative to the valve seat; andan actuation mechanism coupled to the valve closure member and operable to move the valve closure member relative to the valve seat to control flow of fluid through the device, the actuation mechanism comprising a pressure-actuated relief mechanism, comprising, first and second members cooperatively defining opposing surfaces of a fluid chamber such that fluid substantially filling the chamber maintains the first and second members in a first, spaced, relation to one another; anda pressure-responsive fluid valve in communication with the fluid-filled chamber to release fluid from the chamber when the fluid pressure in the chamber reaches a threshold pressure. 2. The well fluid flow control device of claim 1, wherein the first member is a driven member, and wherein the second member is coupled to the valve closure mechanism. 3. The well fluid flow control device of claim 1, wherein the actuation mechanism comprises a linearly movable drive mechanism. 4. The well fluid flow control device of claim 1, wherein the linearly movable drive mechanism comprises an actuation screw. 5. The well fluid flow control device of claim 1, wherein the pressure-responsive fluid valve comprises a burst disk, and wherein the burst disk is configured to rupture at the threshold pressure. 6. The well fluid flow control device of claim 1, wherein the second member is a portion of a valve member drive assembly. 7. A well choke assembly, comprising, a housing assembly defining a flow path extending between a choke inlet and a choke outlet;a valve seat in the flow path;a valve member linearly moveable relative to the valve seat; andan actuation assembly operatively coupled to linearly move the valve member relative to the valve seat, the actuation mechanism including two members coupled in spaced relation at a first distance by a retained fluid column between the two members, and further including a relief valve to release at least a portion the retained fluid column once pressure of the retained fluid reaches a threshold level. 8. The well choke assembly of claim 7, wherein release of the retained fluid causes the distance of spaced relation between the two members of the actuation mechanism to reduce to a second distance lesser than the first distance. 9. The well choke assembly of claim 8, wherein the reduction of the distance of spaced relation between the two members to the second distance reduces the length of the actuation assembly. 10. The well choke assembly of claim 7, wherein the pressure on the retained fluid column is responsive to the pressure on the valve member within the flow path. 11. The well choke assembly of claim 7, wherein the relief valve comprises a burst disk, and wherein the burst disk is configured to rupture in response to fluid pressure in the retained fluid column at the threshold level. 12. The well choke assembly of claim 7, wherein the actuation assembly comprises: an actuator housing assembly;an actuation screw within the actuator housing assembly; anda fluid coupling assembly coupled to the actuation screw; andwherein the fluid coupling assembly comprises, a housing assembly defining a fluid piston chamber, in which a first end of the fluid piston chamber includes the first member, anda piston within the fluid piston chamber, in which the piston includes the second member and further forms a part of an operator stem, andwherein the restrained fluid column is located within the piston chamber between the first and second members; andwherein the valve member is coupled to the operator stem. 13. The well choke assembly of claim 12, further comprising a biasing mechanism oriented to bias the first and second members away from one another to spaced relation at the first distance. 14. A method of assembling a well choke, comprising: coupling a valve member in moveable relative to a valve seat supported by a valve housing assembly, the valve member to regulate fluid flow through a flow passage defined in part by the valve seat, performed by steps comprising, providing a linearly moveable drive mechanism and a valve member drive piston;coupling the linearly moveable drive mechanism to the valve member drive piston through a fluid coupling by placing a portion of the drive piston within a fluid chamber, and coupling the fluid chamber to the linearly moveable drive mechanism, wherein the fluid chamber is defined in part by a pressure-responsive valve mechanism, responsive to pressure within the fluid chamber; andfilling the fluid chamber with a generally incompressible fluid to form a fluid column maintaining the drive piston spaced at a first distance from the linearly moveable drive mechanism; andcoupling the valve member drive piston to the valve member such that linear movement of the linearly moveable drive mechanism will be communicated through the fluid column to the valve member. 15. The method of assembling a well choke of claim 14, further comprising biasing the drive piston in a direction opposite the linearly movable drive mechanism to space it at the first distance from the linearly movable drive mechanism. 16. The method of assembling a well choke of claim 14, wherein the pressure responsive valve mechanism comprises a burst disk. 17. A method of assembling a well choke, comprising: assembling a telescoping valve member drive mechanism within a housing assembly, the telescoping valve member drive mechanism comprising a fluid chamber through which an actuation screw is fluidically coupled to a valve element, the valve element configured to selectively engage a valve seat supported within the housing assembly, wherein the valve element is coupled to a drive assembly that includes a piston located within the fluid chamber;filling the fluid chamber with an essentially non-compressible fluid to bias the drive assembly piston toward a first end of the fluid chamber; andinstalling a pressure responsive relief valve in fluid communication with the fluid chamber, the relief valve configured to open the fluid chamber in response to pressure in the fluid chamber reaching a threshold level. 18. The method of assembling a well choke of claim 17, wherein the pressure responsive relief valve comprises a burst disk. 19. The method of assembling a well choke of claim 17, further comprising installing a biasing mechanism to bias the drive assembly piston toward the first end of the fluid chamber. 20. The method of assembling a well choke of claim 17, wherein the valve element drive assembly is arranged to communicate pressure applied on the valve element to the fluid within the fluid chamber.