Plans have been developed for a series of interventions via the BOP and it is currently anticipated that these may be carried out over a period of about a week, commencing in the next few days. These interventions have not been carried out at these depths and conditions before and the success of individual options cannot be assured.

The first planned intervention is the so-called ‘top kill’ operation where heavy drilling fluids will be injected into the well to stem the flow of oil and gas and, ultimately, kill the well. Most of the equipment is on site and preparations for this operation continue, with a view to deployment within a few days.

If necessary, equipment is also in place to combine this operation with the injection under pressure of bridging material to seal off upward flow through the BOP, the company said.

Sophisticated diagnostic work using remotely-operated vehicles (ROVs) will precede the ‘top kill’ to allow the procedure to be planned in detail. The knowledge from this diagnostic work will be instrumental in determining whether to proceed with this option.

Being progressed in parallel with plans for the top kill is development of a lower marine riser package (LMRP) cap containment option. This will first involve removing the damaged riser from the top of the BOP, leaving a cleanly-cut pipe at the top of the BOP’s LMRP.

The LMRP cap, an engineered containment device with a sealing grommet, will be connected to a riser from the Discoverer Enterprise drillship and then placed over the LMRP with the intention of capturing most of the oil and gas flowing from the well and transporting it to the drillship on the surface. The LMRP cap is already on site and it is anticipated that this option will be available for deployment by the end of May.

Additional options also continue to be progressed, including the option of lowering a second blow-out preventer, or a valve, on top of the MC 252 BOP, BP said.