Patent Number: 6,305,477

Title: Apparatus and method for maintaining relatively uniform fluid pressure within an expandable well tool subjected to thermal variants

Abstract: A thermal compensating apparatus and method for maintaining a relatively constant fluid pressure within a subterranean well tool of the type that is responsive to a source of actuation fluid for manipulating said tool at a location in a well to at least one of sealing and anchoring positions. A body includes a fluid chamber within the body for housing a substantially incompressible fluid for manipulating said tool to at least one of the positions. The fluid chamber is expandable and contractible, for example, through movement of a piston, in response to manipulation of the tool and thereafter in response to thermal variations of the fluid in the fluid chamber. An energy storage and release mechanism, for example, a compression spring, is responsive to pressure changes in the fluid chamber for expanding or contracting the fluid chamber in response to pressure variations in the fluid for maintaining the fluid at a relatively constant pressure.

Inventors: Carisella; James V. (Harahan, LA), Wilson; Paul J. (Houston, TX)

Assignee: Weatherford International, Inc.

International Classification: E21B 33/12 (20060101); E21B 33/127 (20060101); E21B 033/122 ()

Expiration Date: 10/23/2018