Patent ID: 6360822
Filing Date: 2002-03-26
Classification: E21B

Abstract:
In a subsea wellhead system having a wellhead housing secured to a first string of casing, a production casing hanger having an interior surface and an exterior surface and landed in the wellhead housing and secured to a production casing inside the first string of casing and extending below the production casing hanger, a casing hanger packoff that seals between the exterior surface of the production casing hanger and the wellhead housing, and a tree assembly that lands on the wellhead and has an axial bore, the improvement comprising:a casing hanger communication passage passing through the production casing hanger from the exterior surface of the production casing hanger below the production casing hanger packoff to the interior surface of the production casing hanger; and a port closure sleeve having an exterior surface and an interior surface, the port closure sleeve releasably securing to the interior surface of the production casing hanger, the port closure sleeve having an exterior portion that seals against the interior wall portion of the casing hanger to close and isolate the casing hanger communication passage from communication with the interior of the port closure sleeve; the port closure sleeve being retrievable through the bore of the tree assembly after drilling has been completed.