Adjustable mandrel hanger for a jackup drilling rig

Abstract

An offshore well system for a jackup drilling rig enables tensioning of the upper casing strings. An upper running tool is secured to a mandrel, which in turn is connected to the upper casing string. A locking member is located on the mandrel and lands on an internal shoulder in the surface wellhead while the upper string is being lowered by the upper running tool through the surface wellhead. The locking member has a cocked position which allows further downward movement of the mandrel after the locking member has landed on the internal shoulder. A torque member connected between the upper running tool and the mandrel allows left-hand rotation of the upper casing string without risk of the upper running tool unscrewing from the mandrel. This exposes wash ports for circulating fluid back up the annulus around the upper casing string. Flow passages in the locking member allows cement returns and circulation during washout operations after the locking member has landed on the internal shoulder. The locking member is released from the cocked position to a weight supporting position by moving an actuating sleeve upward. The upward movement of the actuating sleeve also frees the torque member to move to a released position. This enables the upper running tool to be unscrewed from the mandrel at the conclusion of the operation.