BOP – BLOW OUT PREVENTER
On semi-submersible rigs and drill ships the BOP is positioned on the wellhead above the sea bed. The BOP pictured has six ram-type preventers and two annular-type preventers, has an inner diameter of 18 ¾ inches and is pressure rated to 15000 psi. The configuration of the stack preventers is optimized to provide maximum pressure integrity, safety and flexibility in the event of a well control incident. Providing redundancy, the BOP is operated via either the yellow or blue control pods shown in the picture.
The drilling rig is connected to the BOP with a riser piping system providing a conduit for tubulars and drilling fluid in the well. The riser is held in tension to prevent buckling by the tensioning system shown in the picture. The tensioning system compensates for the heave of the vessel holding a near constant tension on the riser. It is a N-line tensioning system shown rated to 3.5 million pounds.