Patent ID: 8157005

Claim:
A casing mandrel and a tubing head for an independent screwed wellhead, comprising in combination: a casing mandrel body locked in a casing bowl of the independent screwed wellhead by a casing bowl nut, the casing mandrel body having an axial passage therethrough, a seal bore at a top of the axial passage with a larger diameter than the axial passage, and a casing mandrel top end that extends above a top of the casing bowl nut and includes a pin thread located above the top of the casing bowl nut; and the tubing head comprises one or more ports that communicate with an axial passage through the tubing head; a bottom end received in the axial passage of the casing mandrel below the seal bore, a top end with a tubing bowl that receives a tubing mandrel, and an outer side of the top end includes a pin thread engaged by a tubing bowl nut that locks a tubing mandrel in the tubing bowl.