When a drilling rig leaves a well head, a temporary cap is threaded into position using the drill string, up until now it has needed a drilling rig to undo this cap, prior to explosive removal of the Well.

The equipment developed by Oceantech to overcome this problem is known as a Subsea, TA Cap Removal System. The system is lowered from a DSV by crane to the divers in position on the well head below. The system is fitted with buoyancy bags to enable divers to manoeuvre it into position and release the crane to the surface. Once clamped in position, hydraulic tongs apply rotational pressure to remove the threaded cap.

The well head is then cut free using an explosive charge lowered into the well to a measured distance below the sea bed level, and the well head is removed to the surface for disposal.

The costs and time saved by using the Oceantech Subsea, TA Cap Removal System are enormous and it is envisaged that the system will be widely used as more and more redundant wells are abandoned and the big clean up begins.

See Appendix

Ocean Technical Services Ltd can be contacted in Great Yarmouth on 01433 334400.