With the top kill procedure having failed, BP is moving on to its next attempt: the placement of a containment cap on the Lower Marine Riser Package (LMRP). (Earlier post.) The LMRP is the top half of the blowout preventer (BOP) stack. This procedure is not intended to stop the well from flowing; it is intended to capture the flow while other procedures to cap the well are underway. The basic procedure, as outlined by BP, is to:
First remove the damaged riser from the top of the BOP. A remote operated hydraulic shear will be used to make two initial cuts and then that section will be removed by crane. A diamond wire saw will then be placed to cut the pipe close to the LMRP and the final damaged piece of riser will be removed.
Riser removal. Source: BP. Click to enlarge.
The LMRP Cap is designed to seal on top of the riser stub. The seal will decrease the potential of inflow of seawater as well as improve the efficiency of oil recovery. Lines carrying methanol also are connected to the device to help stop hydrate formation.
The device will be connected to a riser extending from the Discoverer Enterprise drillship.
Analysis and discussion of the LMRP cap attempt is on The Oil Drum here.