WASHINGTON — BP's Deepwater Horizon well, which for 87 days spewed millions of barrels of crude oil into the Gulf of Mexico in the worst accidental oil spill the world has ever seen, has been successfully killed by thousands of tons of heavy drilling mud.
BP announced early Wednesday that a so-called "static kill" had succeeded in forcing the Macondo well's oil back into rock formations 18,000 feet below the sea's surface.
"The MC252 well appears to have reached a static condition," BP said in a news release, calling the well by the Mississippi Canyon lease number it was assigned when BP bought the rights to drill from the federal government in 2008.
The well reached it's "static condition" — meaning the drilling mud was holding the oil in the reservoir by nothing more than its weight — about eight hours after technicians began pumping the mud into the well, BP said. It was midnight on the East Coast, but still Tuesday in the Central time zone, the 105th day of the crisis.
Ironically, it was drilling mud that had signaled the start of the disaster on April 20, when a sudden surge of methane gas shot up the drill pipe, wrapping the Deepwater Horizon offshore drilling rig, with 126 crew and passengers on board, in a huge cloud of flammable gas 48 miles off the Louisiana coast. Alwin Landry, standing watch on the support vessel Damon B. Bankston, which was tied up next to the rig, knew something was terribly wrong. "I saw mud falling on the back of my boat, sort of a black rain," he told a panel investigating the disaster.
Two minutes later, at approximately 9:53 p.m. Central time, the gas, ignited by a spark from an engine, exploded, killing 11 workers, and setting off the catastrophe that has transfixed the Gulf region since — and likely will continue to do so for years to come.
BP said the well will now be monitored to make certain the oil remains in its rock formation. Technicians will determine, perhaps as soon as today, whether to follow the mud with cement that would seal the well permanently.
"The well pressure is now being controlled by the hydrostatic pressure of the drilling mud, the desired outcome of the static kill procedure," BP said in its statement. "Further pumping of mud may or may not be required depending on the results observed during monitoring. BP will continue to work with the National Incident Commander and other government officials to determine the next course of action, which includes assessing whether to inject cement in the well via the same route."
The static kill of the well, in a process oil workers call "bullheading," came 18 days after BP stopped the oil from flowing into the Gulf with a containment cap. That cap was installed on July 15, the 87th day of the disaster. By then, government scientists estimated Monday, 4.9 million barrels of crude had flowed from the well, 4.1 million of that escaping into the ocean.
But the containment cap still could have leaked as the oil slowly backed up behind it. Pressure had reached nearly 7,000 pounds per square inch inside the cap before the static kill procedure got underway Tuesday.
In contrast, there was no upward push inside the containment cap early Wednesday, with the drilling mud resting atop the oil and holding it in place.
BP and government officials say they still plan to complete a relief well that has been underway since May 2 — Day 12 of the disaster — to insure that the well is sealed completely.
That well, long touted as the only sure way of killing the runaway well permanently, is now just 100 feet vertically and four feet horizontally from its goal. Still, it won't likely be in a position to intercept the well before Aug. 15, too late perhaps to have a significant role in the Deepwater Horizon well's demise. By then, cement injected through the static kill procedure already may have done the job.