Patent ID: 7775288

Claim:
A retrievable frac mandrel and well control stack for facilitating completion, re-completion or workover of a cased well having a wellhead with a tubing head spool, comprising: the frac mandrel having a top end and a bottom end that are separate pieces interconnected by a threaded connection with a fluid seal to prevent a migration of stimulation fluids between the separate pieces, the bottom end being contoured to be received in the tubing head spool and to be locked in the tubing head spool by tubing head spool lock down screws that engage an annular groove in the bottom end, and to further provide a high-pressure fluid seal with a seal bore located above a bit guide of the tubing head spool; a well control adapter that mounts to a top flange of the tubing head spool, the well control adapter including an axial seal bore that receives the top end of the frac mandrel to provide a high-pressure fluid seal around a periphery of the top end, and an axial passage that has a diameter smaller than an outer diameter of the top end of the frac mandrel but at least as large as an internal diameter of the frac mandrel; and flow control equipment mounted to a top flange of the well control adapter.