| 摘要 |
An actuating apparatus 12 for a downhole valve 10 comprises an actuating member 48 that is operable by application of fluid pressure from a region uphole of the apparatus 12, either through the inside of production tubing 22 or in a second embodiment through an annulus region, via an inlet port42 which extends at least partially through a tubular body 30, when open, to actuate the valve 10. The actuator 12 is primed when a mechanically actuated sleeve 48 is moved upon withdrawal of a stinger or washpipe, opening the inlet port 42 to tubing or annulus pressure which moves a spring assisted piston 56, displacing hydraulic fluid through an outlet port 44 and conduit 46 to the actuate the downhole valve 10. The apparatus provides a secondary actuator as a contingency or back-up to actuate a downhole valve that has failed to operate in response to a primary actuator or when disconnected during well workover. |
