Tubing hanger landing string with blowout preventer operated release mechanism

摘要

A coupling is incorporated in the landing string which is non-destructively unlatched by the closure of BOP pipe rams. The coupling is simple and reliable to operate in emergencies. When the pipe rams are closed, the radial force releases a mechanism comprising captive pins and an outwardly biased split ring. The split ring is compressed inwardly, releasing shoulders on collet fingers from beneath an undercut in a bore of the coupling. Reconnection is simply achieved by re-engaging the collet fingers in the undercut. Other BOP closure element non-destructively operated landing string couplings are also disclosed.