HOUSTON—An operation that pumped heavy drilling mud to plug BP’s runaway oil well in the Gulf of Mexico has been so successful that Obama administration officials said on Wednesday they are convinced it will never leak again.
BP began the effort, known as a static kill, late Tuesday and stopped pumping after about eight hours to verify that they had filled the Macondo well with mud without springing any new leaks.
Senior government scientists and BP engineers combed through data throughout the day to evaluate the condition of the well piping and whether it made sense to pour cement for a final plug from a surface ship above the well or through a relief well still being drilled.
Technicians said a decision whether to fill the well with cement this week might come later in day. But they said there was no doubt the static kill represented a major step in finally bringing the volatile well under control.
“We have reached a static position in the well that allows us to have high confidence that there will be no oil leaking into the environment,” retired Coast Guard Adm. Thad W. Allen, head of the federal spill response told reporters at a White House briefing. “And we have significantly improved our chances to finally kill the well with the relief well.”
The successful maneuver came almost four months after the well blew out, gushing nearly 780 million litres of crude into the Gulf of Mexico and killing 11 rig workers aboard the Deepwater Horizon platform on April 20. For nearly three months engineers repeatedly failed in their attempts to cap or contain the spill, until they finally were able to fit a tight fitting cap on the well three weeks ago.
President Obama, who had suffered political damage from the perception that he was slow to respond to the crisis, hailed what he called “the welcome news.” In a speech to the A.F.L.-C.I.O., he said, “The long battle to stop the leak and contain the oil is finally close to coming to an end.”
In the static kill procedure, engineers poured an estimated 2,000 barrels of mud at slow but gradually accelerating speeds from a surface vessel through a choke line into the blowout preventer on top of the well and into the oil reservoir.
Engineers still must determine if there are any leaks anywhere outside the production casing, an effort that requires careful readings of pressure fluctuations in the well. If there are no new leaks, government scientists and BP engineers will probably decide to plug the well with cement from the top, engineers following the process said.
But if they find leaks, the engineers said, they will need to fill the well with cement from the bottom through one of two relief wells being drilled. The first relief well, now 30 metres from intersecting the well, is scheduled to be completed by Aug.15. A second will be done shortly after that in case the first well misses its mark.
The static kill may only plug the centre of the well pipe, and not the portion of the well called the annulus between the inner piping and the outer casing. The relief well can intercept both, if the static kill cannot fill the entire pipe.
In the end, BP and government technicians may decide to plug the well with cement both from the top and the bottom for extra insurance that the well will never leak again.