Abstract: A method for sealing a wellhead assembly having a first outer tubular member, a second outer tubular member mounted on the first outer tubular member and an inner tubular member landed in the first outer tubular member. The method includes: providing a packoff assembly having a lower packoff which is releasably connected to an upper packoff releasably connecting an installation tool to the upper packoff; positioning the lower packoff between the inner tubular member and the first outer tubular member and the upper packoff between the inner tubular member and the second outer tubular member; locking the lower packoff to the first outer tubular member; disconnecting the installation tool from the upper packoff; removing the second outer tubular member from the first outer tubular member; removing the upper packoff from the lower packoff; and mounting a third outer tubular member on the first outer tubular member.

Abstract: A method for sealing a wellhead assembly which is initially configured for use in performing a first operation and is subsequently configured for use in performing a second operation. The wellhead assembly in the initial configuration includes a first outer tubular member, a second outer tubular member which is mounted on the first outer tubular member, and an inner tubular member which is landed in the first outer tubular member. The wellhead assembly in the subsequent configuration includes the first outer tubular member, the inner tubular member which is landed in the first outer tubular member, and a third outer tubular member which is mounted on the first outer tubular member in place of the second outer tubular member.

Abstract: A packoff assembly for sealing between an inner tubular member and an outer tubular member has a lower packoff which is configured to seal between the inner and outer tubular members, an upper packoff which is configured to seal between the inner and outer tubular members above the lower packoff, the upper packoff being releasably connected to the lower packoff and, when connected to the lower packoff, being axially movable relative to the lower packoff between a first position and a second position, a latch ring which is supported on the lower packoff, the latch ring being radially expandable into a corresponding locking groove in the outer tubular member, and a locking mandrel which is operably engaged by the upper packoff such that upon axial movement of the upper packoff from the first position to the second position, the locking mandrel expands the latch ring into the locking groove to thereby lock the upper and lower packoffs in position between the inner and outer tubular members.

Abstract: A packoff assembly for sealing between an inner tubular member and an outer tubular member has a lower packoff which is configured to seal between the inner and outer tubular members, an upper packoff which is configured to seal between the inner and outer tubular members above the lower packoff, the upper packoff being releasably connected to the lower packoff and, when connected to the lower packoff, being axially movable relative to the lower packoff between a first position and a second position, a latch ring which is supported on the lower packoff, the latch ring being radially expandable into a corresponding locking groove in the outer tubular member, and a locking mandrel which is operably engaged by the upper packoff such that upon axial movement of the upper packoff from the first position to the second position, the locking mandrel expands the latch ring into the locking groove to thereby lock the upper and lower packoffs in position between the inner and outer tubular members.