Patent ID: 8746347
Filing Date: 2014-06-10
Classification: E21B

Abstract:
1. A subsea wellhead assembly including: a wellhead housing having a generally cylindrical wall configured to support an outer casing string, and further defining an axial bore, the wellhead housing being disposed to support within said bore a casing hanger for the support of an inner casing string within said outer casing string whereby to form a monitoring annulus between the inner and outer casing strings, the wellhead housing including within said wall thereof a communication passageway which is in communication with said monitoring annulus near a lower end of the wellhead housing and which extends upwardly in said wall of the wellhead housing towards an upper end of the wellhead housing; and a valve which is accommodated near the upper end of said wellhead housing and disposed for control from a production tree to control fluid flow passage between (a) the monitoring annulus through said communication passageway within the wellhead housing wall and (b) the production tree while the production tree is in place.