Patent ID: 9458695
Filing Date: 2016-10-04
CPC Classification: E21B

Claim Text:
1. A downhole pressure compensating device for use in combination with a downhole tool, comprising: a housing with a chamber and an internal hollow section, a first piston dividing the chamber into a first section and a second section, the first section being in fluid communication with a first fluid port, the second section being in fluid communication with a borehole through a second fluid port, and a first spring disposed within the second section to exert a pressure on the first piston to enable conservation of an overpressure in the first section, wherein the device further comprises: a second piston, a second spring disposed between the first piston and the second piston, and an overpressure channel arranged in the first or the second piston, and in a compressed condition of the second spring, the overpressure channel, provides fluid communication between said first and second sections.