WELLHEAD SYSTEM FOR TIEBACK RETRIEVAL

摘要

A wellhead assembly includes a casing head, tubing head, and a production tree mounted on the tubing head. An isolation sleeve is set in a main bore of the wellhead assembly that extends across an interface between the casing and tubing heads so that a portion resides in each. The isolation sleeve is configured so that a fracturing string, and its associated hanger, can be retrieved through the isolation sleeve; which significantly reduces the time and steps required to conduct a fracturing operation in a well. Moreover, the present isolation sleeve can be used without changes to existing casing or tubing heads.