Patent ID: 8813852
Filing Date: 2014-08-26
Classification: E21B

Abstract:
1. A subsea wellhead assembly comprising: a production casing hanger defining a series of passageways from an annulus between a production casing string and a relatively outer casing to an interior of said casing hanger and from an interior of said casing hanger through said casing hanger to a region communicable with a production tree, the passageways extending to the interior of the casing hanger, and a positionally adjustable sleeve which fits within the casing hanger and carries exterior seals which are disposed so that for a first position of the sleeve within the casing hanger, fluid passage through the series of passageways by way of said interior is blocked, and for a second position of the sleeve within the casing hanger, said fluid passage is allowed, wherein the sleeve makes screw-threaded engagement with the casing hanger such that movement of the sleeve between said positions can be effected by rotation of the sleeve.