HOUSTON — For more than three months, an oil-weary nation has waited for the moment when engineers would begin pumping cement into BP’s runaway well, in hopes of plugging its flow for good.
That moment arrived quietly on Thursday, with cement following the tons of mud already poured into the well in the operation called a static kill. Because no significant amount of oil has leaked since the well was tightly capped on July 15, the start of the cementing was almost anticlimactic. BP did not even hold its regular daily briefing, saying that Kent Wells, the senior vice president who usually explains the technical details to reporters, was traveling.
Television newscasts, for months fixated on the spectacle of oil gushing from the broken riser pipe on live underwater video, barely covered the transition.
The cement job was completed Thursday afternoon, earlier than expected, a development noted in a brief annoucement by BP. Before the operation’s completion, Thad W. Allen, the retired Coast Guard admiral who heads the federal spill response, told reporters at the government’s midday briefing that the end of the cement pumping would mean “we can all breathe a little easier.”
“This is not the end, but it will virtually assure us there will be no chance of oil leaking into the environment,” he said.
By applying cement to the well from a surface vessel, technicians can plug most, if not all, of the drill pipe and oil reservoir below.
Although the static kill is likely to seal the volatile well permanently, final victory will not be declared until a relief well is completed and it intercepts the well in the middle to later part of August, according to both Admiral Allen and senior BP executives.
The first of two relief wells is still 100 feet from intersecting the Macondo well. It will take five to seven days to complete once the cement applied during the static kill dries by the end of the weekend. A second relief well is being drilled if the first one misses the mark.
Since blowing out on April 20, killing 11 workers aboard the Deepwater Horizon platform, the well has spewed nearly five million barrels of crude oil into the Gulf of Mexico. The tight-fitting capping device that finally stopped the leak three weeks ago was considered a temporary solution.
Because the static kill is not guaranteed to pour cement through the annulus, the portion of the drill pipe between the inner piping and the outer casing, leakage may still remain after the kill, according to officials. But the 18,000-foot relief well can penetrate the entire pipe, after which technicians can test to see how much more cement is needed to kill the well completely.
Technicians working on the static kill said that they could not guarantee that the well was now fully plugged. They said they had not been able to determine whether any oil and gas remained trapped in the casing, drill pipe or annular areas that might have been bypassed by the injection of mud and cement in the static kill operation.
“It’s almost like a mystery you are trying to unravel,” Admiral Allen said. “The question is: what is the path of the cement to the bottom?”
Admiral Allen said the mystery would be solved conclusively only by the relief well, and by a final pumping of mud and cement into any areas not reached by the static kill.