Patent ID: 8066074
Filing Date: 2011-11-29
Classification: E21B

Abstract:
1. A system for mitigating pressure buildup in a wellbore casing annulus of an oil or gas well, said system comprising: a) one or more regions of annular space within the oil or gas well established by at least two casing strings having different diameters and arranged in a nested, concentric manner such that at least a portion of a smaller diameter casing string is situated in at least a portion of a larger diameter casing string; b) at least one chamber that is integrated with a casing joint on at least one of the casing strings, wherein the at least one chamber contains an inert gas, and wherein said gas is introduced to said chamber via a gas fill port that is integrated with said chamber; and c) at least one piston-containing piston assembly integrated with the at least one chamber such that annular liquid present in an annular region can, when increased in pressure, access the at least one chamber via an annular pressure buildup port, so as to move the piston in such a way as to increase pressure of the inert gas in the chamber and decrease, via expansion, pressure of the annular liquid wherein said system further comprises one or more chambers of a second type, wherein said chambers incorporate one or more burst disks separating the chamber from the annular space.