초록 ▼

A control system for a subsurface safety valve (SSV) comprising of a control line from the surface in fluid communication with the top side of an actuating piston which moves a flow tube downwardly to open the SSV. A balance line runs from the surface to the bottom side of the same actuating piston

A control system for a subsurface safety valve (SSV) comprising of a control line from the surface in fluid communication with the top side of an actuating piston which moves a flow tube downwardly to open the SSV. A balance line runs from the surface to the bottom side of the same actuating piston to put the actuating piston in pressure balance. A buildup of pressure in the control line overcomes a return spring to open the valve, while removal of pressure from the control line allows the return spring to close the valve. Seals and leakpaths are provided through the actuating piston so that, depending on the hydrostatic pressure in the control line and the size of the return spring, the various failure modes of the actuating piston seals and control line or balance line will preferentially result in a fail-closed situation in the SSV.

대표청구항 ▼

[ What is claimed is:] [1.] A control system for control of a subsurface safety valve (SSV) for movement of a flow tube therein, comprising:an actuating cylindrically shaped rod piston, sealingly mounted using a plurality of seals in a housing, one of said piston or said housing being operably conne

[ What is claimed is:] [1.] A control system for control of a subsurface safety valve (SSV) for movement of a flow tube therein, comprising:an actuating cylindrically shaped rod piston, sealingly mounted using a plurality of seals in a housing, one of said piston or said housing being operably connected to the flow tube;a control line from said housing to the well surface, said control line in fluid communication with a first end of said piston;a balance line extending from the surface to a second side of said piston, putting said piston in pressure balance with hydrostatic pressure from said control line.