Patent ID: 7159663

Claim:
A hybrid wellhead system, comprising: a plurality of tubular heads connected to form the hybrid wellhead system using threaded unions, each tubular head supporting a tubing mandrel for suspending a respective tubular string in a well, each tubing mandrel extending above a top of the tubular head that supports it; a tubing head spool mounted to a top one of the tubular heads of the wellhead system, the tubing head spool having a bottom annulus which includes an outer shoulder that is engaged by a threaded union for connecting the tubing head spool to the top one of the tubular heads, the tubing head spool supporting a tubing mandrel that is locked in place by a plurality of lock pins and the tubing head spool further having a flanged top end with an annular groove for receiving a standard metal ring gasket for connection of a flow-control stack.