Piston assembly to reduce annular pressure buildup

Abstract

A system for preventing annular pressure buildup comprising: a wellbore; two or more annuli located within the wellbore; a piston assembly located adjacent to a wellhead of the wellbore; and a pipe system that connects the two or more annuli in parallel to the piston assembly, wherein when the amount of pressure in the pipe system exceeds a predetermined amount, then a piston of the piston assembly moves whereby the movement reduces the amount of pressure in the two or more annuli.

What is claimed is: 
     
         1 . A well system for preventing annular pressure buildup, the system comprising:
 a wellbore;   two or more annuli located within the wellbore;   a piston assembly located adjacent to a wellhead of the wellbore; and   a pipe system that connects the two or more annuli in parallel to the piston assembly, wherein when the amount of pressure in the pipe system exceeds a predetermined amount, then a piston of the piston assembly moves whereby the movement reduces the amount of pressure in the two or more annuli.   
     
     
         2 . The system according to  claim 1 , wherein the well system is an off-shore system. 
     
     
         3 . The system according to  claim 1 , wherein the wellhead is located on a sea floor. 
     
     
         4 . The system according to  claim 1 , wherein the wellbore comprises one or more wellbore intervals. 
     
     
         5 . The system according to  claim 1 , wherein at least some of the two or more annuli contain a wellbore fluid. 
     
     
         6 . The system according to  claim 5 , wherein the wellbore fluid exerts a certain amount of pressure within the two or more annuli. 
     
     
         7 . The system according to  claim 1 , wherein at least one annulus of the well system is bounded by a rupture disk or other fluid flow restriction device that restricts fluid flow past the device but fails above a certain pressure rating, and wherein at a pressure above the pressure rating any fluid within the annulus flows into an adjacent annulus. 
     
     
         8 . The system according to  claim 7 , wherein the adjacent annulus is one of the two or more annuli. 
     
     
         9 . The system according to  claim 1 , wherein the pipe system comprises two or more pipes that are connected to a common pipe. 
     
     
         10 . The system according to  claim 9 , wherein the common pipe is connected to the piston assembly. 
     
     
         11 . The system according to  claim 10 , wherein the piston defines two chambers within a housing of the piston assembly, wherein the common pipe feeds into a first chamber on one side of the piston, and wherein a second chamber is located on the other side of the piston opposite of the first chamber. 
     
     
         12 . The system according to  claim 11 , wherein the second chamber contains a compressible gas or mixtures of compressible gases. 
     
     
         13 . The system according to  claim 12 , wherein movement of the piston inversely changes the dimensions of the first and second chambers. 
     
     
         14 . The system according to  claim 13 , wherein the movement of the piston reduces the dimensions of the second chamber via compression of the compressible gas or mixtures of compressible gases. 
     
     
         15 . The system according to  claim 1 , wherein the amount of pressure in the two or more annuli is reduced to at least a sufficient pressure such that damage to wellbore components does not occur. 
     
     
         16 . A method of reducing the amount of pressure in two or more annuli of a wellbore, the method comprising:
 connecting the two or more annuli in parallel to a piston assembly via a pipe system, wherein the piston assembly is located adjacent to a wellhead of the wellbore; and   allowing a piston of the piston assembly to move when the amount of pressure in the pipe system exceeds a predetermined amount, wherein the movement reduces the amount of pressure in the two or more annuli.   
     
     
         17 . The method according to  claim 16 , wherein the piston defines two chambers within a housing of the piston assembly, wherein a common pipe of the pipe system feeds into a first chamber on one side of the piston, and wherein a second chamber is located on the other side of the piston opposite of the first chamber. 
     
     
         18 . The method according to  claim 17 , wherein the second chamber contains a compressible gas or mixtures of compressible gases. 
     
     
         19 . The method according to  claim 18 , wherein movement of the piston inversely changes the dimensions of the first and second chambers. 
     
     
         20 . The method according to  claim 19 , wherein the movement of the piston reduces the dimensions of the second chamber via compression of the compressible gas or mixtures of compressible gases. 
     
     
         21 . The method according to  claim 16 , wherein the amount of pressure in the two or more annuli is reduced to at least a sufficient pressure such that damage to wellbore components does not occur.