BP may attempt early next week to plug an oil leak 5,000 feet (1,524 meters) below the surface of the Gulf of Mexico by stuffing it with drilling mud, a procedure that has never been tried that deep.
Three drilling rigs and 16 remote-operated vehicles are being positioned for the attempt, which could come as soon as May 25, Doug Suttles, chief operating officer for exploration and production, BP, said yesterday at a press conference in Louisiana.
The so-called top kill method calls for mud twice the density of water to be pumped into the well using a Helix Energy Solutions Group rig, Suttles said. The mud should stop the flow so the well can be sealed with cement, he said.
“This operation has been done in land operations and in shallow water, but it has never been done at these depths,” Suttles said. “That presents unique problems.”
BP is using a tube to divert some of the spill to a drill ship. On average, that system has recovered 2,000 barrels of oil a day since it was started on May 16, Suttles said.
BP said on May 20 that the recovery rate had reached the equivalent of 5,000 barrels a day, the same rate it has been giving for the spill since April 28. That led to criticism from US Rep Edward Markey when a video feed he had requested from BP showed oil and gas still leaking into the sea. “At some points in time, we’ve had rates as high as 5,000 barrels a day,” Suttles said. “We’ve never said it produced 5,000 barrels in a day. At points in time, it produced all gas and no oil.”
The 5,000 barrel-a-day rate is still the “best estimate” for the spill, Suttles said.
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Size of leak
A team of government and academic scientists will calculate how much oil is leaking, Jane Lubchenco, administrator of the National Oceanic and Atmospheric Administration said on May 20. The report is expected next week, US Coast Guard Rear Admiral Mary Landry said at yesterday’s press conference. The report would be peer-reviewed and will not be rushed, she said.
In response to a directive from the Environmental Protection Agency, BP notified the agency on the night of May 20 it had found no alternative to Corexit, the oil dispersant it has been using, that is effective and less toxic, Suttles said.
BP has applied more than 6,70,000 gallons of Nalco Holding’s Corexit dispersant from ships, aircraft and remote- operated vehicles at the seabed to break up the oil into droplets.
The EPA directed the company on May 19 to find a less toxic product because the volume of dispersant used is “unprecedented,” and the damage to sea life may outweigh the benefits. BP is willing to test alternatives in cooperation with the EPA, Suttles said.
The US Coast Guard and the Army Corps of Engineers are still evaluating Louisiana’s proposal to dredge sand to fill in gaps in eroded barrier islands to protect wetlands from oil washing ashore, US Coast Guard Admiral Thad Allen said yesterday.