초록 ▼

A subsurface safety valve for use in subterranean oil and gas well which is actuated by pressure fluctuations in the tubing-casing annulus is disclosed. The safety valve assembly consists of a safety valve mounted in a packer which is actuated by a subsurface control located above the packer. Annulu

A subsurface safety valve for use in subterranean oil and gas well which is actuated by pressure fluctuations in the tubing-casing annulus is disclosed. The safety valve assembly consists of a safety valve mounted in a packer which is actuated by a subsurface control located above the packer. Annulus pressure variations are controlled by a surface unit. The subsurface control utilizes a reference pressure chamber in which the pressure is initially adjustable to compensate for hydrostatic pressure in the annulus. Leakage of the gas in a dome pressure chamber in the subsurface control is impeded by the presence of a barrier fluid impervious to the passage of gas therethrough, with the barrier fluid being maintained at a higher pressure than the reference pressure in the dome charged chamber.

대표청구항 ▼

In a subterranean well tool having a shiftable member, reciprocal in response to a force differential between opposite surfaces of said shiftable member, the force on one surface of said shiftable member comprising a force generated by the pressure of a gas; the improvement comprising a barrier flui

In a subterranean well tool having a shiftable member, reciprocal in response to a force differential between opposite surfaces of said shiftable member, the force on one surface of said shiftable member comprising a force generated by the pressure of a gas; the improvement comprising a barrier fluid relatively impervious to the passage therethrough of the gas, said barrier fluid being located between said gas and a region at a pressure differing from the pressure of said gas, said barrier fluid being at a pressure in excess of said reference pressure to retard passage of said gas into said barrier fluid.