BP says the “static kill” of its ruptured Gulf of Mexico oil well has worked, a big step towards sealing it, the oil giant announced early Wednesday. The well-killing procedure, which began Tuesday afternoon, involves pumping heavy drilling mud down from above to push oil back into the well reservoir.
“The well pressure is now being controlled by the hydrostatic pressure of the drilling mud, the desired outcome of the static kill procedure, a BP statement said. “The pumping of heavy drilling mud was stopped after about eight hours of pumping drilling mud down the well. The well is now being monitored, per the procedure, to ensure the well remains static.”
The static kill is the biggest development in the long-running saga involving BP’s well since a tightly fitting cap was placed on it in mid-July, stopping oil from flowing into the Gulf for the first time in almost three months.
Meanwhile, the news comes as the U.S. government is expected to admit that 75% of the oil from the leak has already evaporated, dispersed, or been captured or eliminated.
The Environmental Protection Agency is likely to face questions about its finding that eight dispersants, including one used in combating the Gulf of Mexico oil disaster, are no more toxic when mixed with oil than the oil alone.
Paul Anastas, the EPA assistant administrator for research and development who reported test results earlier this week, will be the lead witness in the Senate hearing. He said the tests prove that the oil itself, not the dispersants, is “enemy No. 1”
In the static kill operation, it’s still unclear whether the mud will be followed by cement, according to BP Senior Vice President Kent Wells. Engineers will evaluate that as they proceed.
They may decide to wait until a relief well is completed in an accompanying well-killing effort known as a “bottom kill” — intended to serve as an insurance policy that the well is sealed. That could happen about a week from now.
Some reporters were allowed on the Q4000, the ship that is pumping the mud, as the static kill got under way. The operation took place under blue skies in clear blue seas — in sharp contrast to scenes in the Gulf weeks ago, when oil covered vast swaths of water.
BP proceeded with the static kill after conducting a crucial test to determine if oil in the capped well could actually be pushed back down into the reservoir and it was safe to proceed. In the “injectivity” test, a surface ship slowly injected small amounts of mud into the well at several different rates to make sure the mud would reach the reservoir.
BP said that all the operations are being carried out with the approval of the federal official overseeing the response to the oil spill, retired Coast Guard Adm. Thad Allen.
The injectivity test had been delayed because of a small hydraulic leak discovered in the capping stack hydraulic control system. But BP and Allen said earlier Tuesday the leak had been fixed by crews overnight.
“The leak involved two valves that are on the kill side of the capping stack and they started to lose pressure. We found that out in time and locked the valve shut. And, had the valves failed for any particular reason, that might have caused hydrocarbons to go into the environment and that’s not good,” Allen said.
Allen emphasized that relief wells being drilled are the “answer” to plugging the ruptured well. “I think all of our hopes and aspirations are that this thing will come to an end,” Allen said, discussing the entire spill ordeal. “It’s been an agonizing period for the people of the Gulf and the United States in general.”
Meanwhile, scientists charged with determining the flow from the leaking well said Monday that roughly 4.9 million barrels (205.8 million gallons) of oil have seeped from it.
About 800,000 barrels of that were retrieved by siphoning vessels on the surface over the leak. Previously, the same group had put the total estimate of oil leaked from the well before it was capped on July 15 at between 3 million and 5.2 million barrels.
And just over 100 days after the Deepwater Horizon drilling rig exploded in the Gulf of Mexico, killing 11 workers, the water around the Gulf is almost entirely clear.
That prompted a wide-ranging response that involved dispersants, burning oil on the surface of the water and gathering it with skimming ships, trying to prevent it from reaching shore with booms and collecting oil debris from beaches across the Gulf with an army of BP workers.
When the BP well was capped in the Gulf of Mexico in July, scientists said some 53,000 barrels of oil per day were leaking from it, while roughly 62,000 barrels of oil were likely gushing from it each day at the beginning of the incident. [via BBC (UK), CBS News and CNN]