Patent Number: 7,610,964

Title: Positive displacement pump

Abstract: A submersible pumping system for use downhole that includes a housing containing an expandable fluid, that when expanded pushes a piston that in turn pumps wellbore fluid to the surface. The expandable fluid can be a silicon based heat transfer fluid with a coefficient of thermal expansion of at least about 0.0005 in.sup.3/in.sup.3/.degree. F. The expandable fluid is expanded upon exposure to heat. A heat source is selectively activated for expanding the fluid.

Inventors: Cox; Don C. (Roanoke, TX)

Assignee: Baker Hughes Incorporated

International Classification: E21B 43/16 (20060101)

Expiration Date: 1/03/02017