SUBSURFACE SAFETY VALVE Russian patent published in 1999 - IPC

FIELD: oil and gas producing industry; applicable in well remedial work. SUBSTANCE: subsurface safety valve includes body, piston with annular groove with chambers for engagement with retainer, rod and packer. Hydraulic channel communicates hollow under piston with hollow under valve. Hollows under piston and under valve are communicated with pipe hollow. Pressure differential causes piston to be released from retainer and piston open valve. Fluid from underpacket zone flows through hydraulic channel in body to abovepacker zone and valve returns to initial position. EFFECT: simplified design, higher reliability in well shutoff and increased time between overhauls. 1 dwg