Downhole isolation and depressurization tool

摘要

A depressurization tool is described for use downhole in depressurizing an isolated zone. A decompression chamber containing a compressible fluid volume is described. The opening of the chamber is sealed with a closure that is configured to open upon application of a pressure differential across the opening. When used downhole within an isolated and nonpermeable wellbore zone, excessive ambient pressure will cause the closure to open and allow the chamber to fill with fluid at increased pressure, depressurizing the wellbore zone. The tool is useful in wellbore completion systems that include sliding sleeves.

主权项

1. A system for use in dissipating pressure in a wellbore, the system comprising:
a housing operatively connected between two casing tubulars of a casing string, the housing including a lateral port defined therethrough; a sliding sleeve associated with the housing, the sliding sleeve being moveable from a first position wherein the sleeve prevents fluid communication from an annulus defined between a tool string and the casing through the port to a second position wherein fluid communication through the port is permitted; and the tool string comprising: at least one sealing element adapted to provide a seal between the tool string and the sliding sleeve; and a decompression chamber disposed on the tool string below the sealing element, the chamber defining a hollow interior and having an opening for admitting fluid from the annulus into the interior of the chamber, the opening being sealed by a closure to sealingly isolate the chamber from the annular fluid between the casing string and the tool string, the closure being releasable upon application of a pressure differential across the closure, wherein movement of the admitted fluid in the annulus permits actuation of the sliding sleeve from the first position to the second position.