초록 ▼

A subsurface safety valve has a tubular valve housing, a valve closure member movable between an open and a closed position, an axially shiftable flow tube for opening the valve closure member. Hydraulic pressure from the control line is used to move a piston, which in turn moves an axially shiftabl

A subsurface safety valve has a tubular valve housing, a valve closure member movable between an open and a closed position, an axially shiftable flow tube for opening the valve closure member. Hydraulic pressure from the control line is used to move a piston, which in turn moves an axially shiftable opening prong through the closure member. A balance line, or second hydraulic line is also used to make the valve well insensitive. An isolation valve is placed in the flow path of the second hydraulic line. The isolation valve prevents gas migration into the balance line. It also provides volume control for the fluid displaced when the piston is moved by pressure from the control line. Further, the valve can be closed by the application of sufficient pressure through the second hydraulic line.

대표청구항 ▼

[ We claim:] [1.]1. A safety valve for use in a well bore having an annulus, said valve comprising:(a) a tubular valve housing;(b) a valve closure member captured in said housing and movable between an open and a closed position;(c) an axially shiftable opening prong captured in said housing for ope

[ We claim:] [1.]1. A safety valve for use in a well bore having an annulus, said valve comprising:(a) a tubular valve housing;(b) a valve closure member captured in said housing and movable between an open and a closed position;(c) an axially shiftable opening prong captured in said housing for opening the valve closure member;(d) a control line for supplying a hydraulic pressure to move the opening prong against the closure member;(e) a balance line coupled to said tubular housing; and(f) an isolation valve coupled to said balance line wherein the isolation valve isolates said balance line from a g as migration from said safety valve.