Combination packer/safety valve assembly for gas storage wells

Abstract

A combination packer/safety valve assembly is connectable to the bottom end of a tubing string and lowerable therewith into the casing string portion of a gas storage well to control the upward flow through the casing string of pressurized gas stored in a subterranean cavern below the casing string. In response to the delivery through the tubing string to the interior of the assembly of control fluid at a first predetermined pressure a normally closed, axially extending interior passage of the assembly is opened to permit upward flow therethrough of pressurized gas for delivery to the well surface through the casing string. An increase of the control fluid pressure to a higher, predetermined second magnitude radially extends an anchor slip and packer structure externally carried by the assembly body into an anchored, sealing engagement with the interior surface of the casing string, and a locking structure automatically functions to hold the anchor slip and packer structure in this radially extended orientation. A subsequent increase of the control fluid pressure to a still higher, predetermined third magnitude causes the anchor slip and packer structure to be driven back to a radially retracted position, thereby releasing the assembly for upward retrieval movement with the tubing string through the casing string.