Safety valve closure system
Apparatus and method of controlling a surface safety valve and a subsurface safety valve in a producing hydrocarbons well,Safety Valves comprising: providing a self contained control circuitry including a reservoir for a hydraulic fluid; sensing a drop below a pre-established level of pressure in a flowline distal to the surface safety valve and a drop below a pre-established level of pressure in a portion of a hydraulic circuit fluidly connected to a subsurface safety valve proximal to the subsurface safety valve,API Cast Steel Valves and responsive to sensing a drop of the pressure in either the flowline or the circuitry proximal to the subsurface valve: first draining fluid to the reservoir from a portion of the circuitry means hydraulically maintaining the surface safety valve open, then after a first time delay sufficient for closure of the surface safety valve, MUD VALVESsecondly draining fluid to the reservoir from a portion of the circuitry means hydraulically maintaining the subsurface safety valve open, and then after a second time delay sufficient for closure of the subsurface safety valve, thirdly isolating the subsurface safety valve at least from the portion of the circuitry means proximal to a subsurface safety valve.
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