Patent ID: 7040410
Filing Date: 2006-05-09
Classification: E21B

Abstract:
1. An adapter for mounting any one of a blowout preventer, a high pressure valve, and a well stimulation tool to a double-locking casing mandrel of an independent screwed wellhead, the adapter comprising: an adapter pin comprising a hollow cylindrical body having a central passage, a top nipple section with a top pin thread, and a bottom nipple section with a bottom pin thread and a sealing nipple located above the top pin thread, the bottom nipple section being received in an axial passage of the double-locking casing mandrel and the bottom pin thread engaging a top end box thread in the central passage of the double-locking casing mandrel; and one of: a lockdown flange comprising a top end to which the blowout preventer, the high pressure valve, or the well stimulation tool can be mounted; the lockdown flange including an axial passage having a box-threaded bottom end for receiving the top nipple section of the adapter pin and threadedly engaging the top pin thread thereof and a lockdown nut supported by an annular shoulder below the top end, the lockdown nut having a box thread for engaging a pin thread on an outer wall of a top end of the double-locking casing mandrel; and a retainer flange for providing a mounting surface to which the any one of the blowout preventer, high pressure valve, and well stimulation tool can be mounted, the retainer flange comprising an annular flange with an axial passageway that is box-threaded for engaging a pin thread on a top end of the double-locking casing mandrel.