Subsea wellhead apparatus

摘要

There is disclosed subsea wellhead apparatus which includes a tubing hanger supported within the bore of a wellhead housing and having a passageway through it connecting the annulus between the casing and tubing strings suspended from the hangers with the bore of the housing above the tubing hanger. The passageway is opened and closed by a valve member carrying metal seal rings, and the integrity of the seals is tested by test pressure from a reservoir contained in the tubing hanger.