Temperature compensated accumulator

摘要

A temperature compensated accumulator and method for use thereof downhole in a well. The accumulator may include a housing with separate bulkhead and piston assemblies. Thus, one assembly may include a hydraulic fluid chamber separated from a gas precharge pressure chamber by a piston and the other assembly may include an ambient pressure chamber separated from an atmospheric chamber by another piston. Additionally a pressure relief and check valve assembly may be located at a pressure relief chamber between the other assembly sections. Thus, venting to or from the gas precharge pressure chamber may take place upon exposure to a predetermined decreased or elevated temperature so as to maintain a substantially constant precharge level for the accumulator, for example, in spite of dramatic changes in downhole temperatures.

主权项

1. A temperature compensated accumulator comprising:
a generally cylindrical housing having a first longitudinal end and a second longitudinal end, each longitudinal and having a port therein, the housing divided into three sections, including a centrally sealable pressure relief chamber, by two longitudinally spaced apart bulkheads; a first piston disposed in the housing on one side of a first of the two bulkheads, the first piston separating a hydraulic fluid chamber and a gas precharge pressure chamber; a second piston disposed in the housing on one side of a second of the two bulkheads, the second piston separating an ambient pressure chamber and an atmospheric chamber; a connecting rod disposed between the first and second pistons; and a pressure relief valve and a check valve in pressure communication between the gas precharge pressure chamber and the pressure relief chamber, the pressure relief chamber defined between the first bulkhead and the second bulkhead, the pressure relief chamber including a longitudinally movable pressure barrier responsive to downhole temperature variations, the pressure relief valve set to a preselected value within a range of pressure safely containable by the housing, the pressure barrier engageable with a stop feature on the connecting rod such that an increase in pressure of the ambient pressure chamber compresses gas discharged into the pressure relief chamber back into the gas precharge pressure chamber through the check valve.