May 12, 2010
BP prepares for top kill
As oil and gas continued to spew into the Gulf of Mexico, BP said its subsea efforts to deal with the Deepwater Horizon leak continue to focus on options to stop the flow of oil from the well through interventions via the blow out preventer (BOP) and on attempts to contain the flow of oil at source to reduce the amount spreading on the surface. These efforts are being carried out in conjunction with governmental authorities and other industry experts.
Further investigation of the failed BOP, using remotely-operated vehicles and a variety of diagnostic techniques, has, says BP "increased our understanding of the condition of the BOP" and allowed planning to continue for a number of potential interventions, including a "top kill" of the well.
The condition of the BOP was a key issue at a congressional hearing Wednesday.
This would involve first injecting material of varying densities and sizes (also known as "junk shot") into the internal spaces of the BOP to provide a seal, before pumping specialized heavy fluids into the well to prevent further flow up the well. Plans for this option are being developed in preparation for potential application next week.
Work to deploy a second system designed to contain the oil flow subsea has continued. A small dome or "top hat" has been taken out to the well site and placed on the seabed in preparation for deployment. Such a system has never been used in water depths of 5,000 feet and its successful operation is not certain. The deployment of this system is expected to be attempted within the next few days.
BP says that all of the techniques being attempted or evaluated to contain the flow of oil on the seabed involve significant uncertainties because they have not been tested in these conditions before.