Hybrid two piece packoff assembly

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. The method includes the steps of (a) providing a packoff assembly which includes a lower packoff that is releasably connected to an upper packoff, the lower packoff being configured to seal between the inner tubular member and the first outer tubular member and the upper packoff being configured to seal between the inner tubular member and the second outer tubular member; (b) releasably connecting an installation tool to the upper packoff; (c) using the installation tool, lowering the packoff assembly as a unit through the second outer tubular member until the lower packoff is positioned between the inner tubular member and the first outer tubular member and the upper packoff is positioned between the inner tubular member and the second outer tubular member; (d) using the installation tool, locking the lower packoff to the first outer tubular member to thereby secure the lower packoff in position between the inner tubular member and the first outer tubular member and the upper packoff in position between the inner tubular member and the second outer tubular member; (e) disconnecting the installation tool from the upper packoff; (f) after the first operation is performed, removing the second outer tubular member from the first outer tubular member; (g) removing the upper packoff from the lower packoff; and (h) mounting the third outer tubular member on the first outer tubular member. During this procedure, steps (c) and (d) are performed in a single trip, and the lower packoff remains locked in position between the inner tubular member and the first outer tubular member from step (d) through step (h).

Dependencies are inferred from the claim text.