| 摘要 |
A housing can be mounted adjacent an isolation valve and after a fixed number of on and off pressure cycles allow a spring to push an actuator to operate the valve to an open position. The actuator, in another embodiment, can be reset with a tool run into the module to move the actuator back against a power spring and hold that spring force until the pressure cycling begins again. The preferred application is for a formation isolation ball valve but other valves, such as sliding sleeves, or other types of downhole tools can be actuated with the module that permits a retrofit of a hydraulic operation to a heretofore purely mechanically actuated tool. The actuation force to initially open is boosted by a secondary potential energy source that is unlocked to give an initial boost force to the indexing spring that is part of a j-slot actuation mechanism. |
