Independent dual actuated subsurface safety valve

摘要

A downhole valve for use in a well has a closure device that is biased closed to seal against flow through the central bore of the valve. A plurality of pistons are each coupled to a respective hydraulic control line into the valve. Each piston is adapted to reside in an actuated position, supporting the closure open, when at least a specified hydraulic pressure is supplied through its control line, and to reside in an unactuated position, not supporting the closure open, when at least the specified hydraulic pressure is not present in its control line. The valve has a chamber containing a hydraulic fluid hydraulically coupling the pistons to support any piston not receiving the specified hydraulic pressure in an unactuated position. In certain aspects, when the piston is in the unactuated position, it seals against communication of fluid with its respective control line using a static-type seal.

主权项

1. A subsurface safety valve for use in a subterranean well, the valve comprising:
a tubular body defining a flow bore therethrough; a closure in the tubular body, the closure changeable between sealing against flow through the flow bore and allowing flow through the flow bore; a first piston having a first control line inlet arranged to receive a first control pressure from a first control line, the first piston movable from a first unactuated position to a first actuated position in response to the first control pressure; a second piston having a second control line inlet arranged to receive a second control pressure from a second control line, the second piston moveable from a second unactuated position to a second actuated position in response to the second control pressure; the first and second pistons coupled to the closure to change the closure between sealing against flow through the flow bore and allowing flow through the flow bore when the first and second pistons are respectively moved to the first and second actuated positions; the first and second pistons hydraulically coupled to one another to support the first piston in an unactuated state when the second control pressure applied to the second piston is greater than an actuation pressure and the first control pressure applied to the first piston is less than the actuation pressure; the first and second pistons are coupled to one another to support the first piston in an unactuated state when the second control pressure applied to the second piston is greater than the first control pressure applied to the first piston via a hydraulic fluid in a hydraulic fluid chamber of the valve; and the chamber is pressure balanced with the flow bore.