US 7,591,317 B2
Tubing pressure insensitive control system
Darren E. Bane, Broken Arrow, Okla. (US); David Z. Anderson, Glenpool, Okla. (US); and Aaron T. Jackson, Broken Arrow, Okla. (US)
Assigned to Baker Hughes Incorporated, Houston, Tex. (US)
Filed on Nov. 09, 2006, as Appl. No. 11/595,607.
Prior Publication US 2008/0110611 A1, May 15, 2008
Int. Cl. E21B 34/10 (2006.01)
U.S. Cl. 166—375  [166/321; 166/324] 22 Claims
OG exemplary drawing
 
1. A control system for an operating mechanism in a downhole tool from a single control line extending from the surface, comprising:
a tool housing having a passage and at least one control line connection for fluid communication to the single control line;
at least one piston having a first portion in fluid communication with said control line connection, a second portion in pressure balance from exposure to said passage and a third portion defining, at least in part, a variable volume chamber isolated from said passage and from a hydrostatic force to offset the hydrostatic pressure in the control line and operating at about atmospheric pressure.