External Production Riser Tieback Connector

A tieback connector 11 comprises a passive lower locking system 47 and an active upper locking system 45 to exert a positive locking force on the connection between a production riser 13 and a high pressure wellhead 15. The tieback connector 11 is comprised of an outer housing 27 which carries lower locking dogs 51, upper locking dogs 119 and a piston 87. The piston is located above the lower end of the production riser 13 and controls the movement of the outer housing 27. As the piston 87 is stroked the outer housing 27 cams the lower dogs 51 into grooved profile 55 in the wellhead housing 15. As the piston 87 is stroked further the upper dogs 119 exert a force onto the production riser 13 that locks the riser 13 to the wellhead housing 15.