BP has successfully plugged its leaking oil well in the Gulf of Mexico by pumping heavy mud into it.
The ‘static kill’ operation – deemed a ‘significant milestone’ by BP – was completed this morning after eight hours of pumping.
However, a government official cautioned that the well would not be permanently sealed until it was filled with cement using relief wells, the first of which is expected to reach its target intercept point towards the end of next week.
‘The well pressure is now being controlled by the hydrostatic pressure of the drilling mud, which is the desired outcome of the static kill procedure carried out yesterday,’ BP said in a statement.
‘The aim of these procedures is to assist with the strategy to kill and isolate the well, and will complement the upcoming relief well operation, which will continue as per plan.
‘A relief well remains the ultimate solution to kill and permanently cement the well.’
Coastguard admiral Thad Allen, leader of the government’s response team, said: ’The static kill will increase the probability that the relief well will work. But the whole thing will not be done until the relief well is completed.
‘The static kill is not the end all be all. It is a diagnostic test that will tell us a lot about the integrity of the casing and the wellbore.’
The operation followed an injectivity test to establish the pumping could be done and what pressures to expect. BP’ senior vice president, Kent Wells, said: ‘The injectivity test was textbook. It went exactly as we would have expected.’
BP is continuing to monitor the wellhead, which was capped over two weeks ago. Research vessels are conducting seismic and acoustic tests around the wellhead, and pressure monitors show the pressure within the well is slowly rising, suggesting oil is not leaking out.
Scientists have called the disaster the biggest unintentional oil spill ever, after calculating that 4.9 million barrels of oil escaped from the well, 4.1 million of which was released into the ocean.
According to the New York Times, the US government is expected to announce today that three-quarters of the oil has already evaporated, dispersed, been captured or otherwise eliminated, and that the rest is so diluted it does not pose much risk.