| 摘要 |
A control system for the operation of the subsurface safety valve is disclosed. The control system uses a pressurized gas chamber, as well as a shuttle valve which connects to the main fluid pressure supply from the surface. The shuttle valve is connected to the gaseous chamber as well as to a barrier piston. As a result of the arrangement, leakages between the downstream side of the operating piston and the shuttle valve result in a reestablishment of the pressure balance on the operating system which allows the subsurface safety valve to close. Additionally, in the event of loss of gaseous pressure, the same pressure-balancing effect occurs on the operating piston, which allows the subsurface safety valve to go to a closed position. The configuration of the control system, which includes a gaseous chamber, allows for disconnection of the hydraulic fluid supply before the predetermined depth is reached to facilitate the connection of a tubing hanger. |
