BP begins "static kill" at ruptured US oil well
Oil company BP Plc on Tuesday began the long-awaited pumping of mud into the ruptured well in the Gulf of Mexico - the so-called "static kill" to permanently seal the shaft, dpa reported.
If the mud injection succeeds in overcoming the upward pressure of oil in the well, which stretches 5-kilometre below the sea floor, engineers would follow by pumping in cement.
A spokesman for BP in London told the German Press Agency dpa that the static kill attempt at the well, 60 kilometres off the Louisiana coast, had begun at 3 pm (1900 GMT).
The well exploded April 20 and has become what federal scientists say is the biggest accidental oil spill in world history.
The heavy mud is specially engineered to weigh down against the pressure of oil being pushed out of the deep oil reservoir. BP has several ships with high pressure pumps to inject the mud.
Testing on the well cap to see if the mud injection could proceed was successful earlier Tuesday. The testing had been delayed Monday night by a hydraulic leak discovered in the well cap.
The static kill manoeuvre is expected to last until at least late Wednesday and perhaps until Friday, said retired Coast Guard Admiral Thad Allen, who is overseeing the containment and kill operations for the US government.
A similar procedure, the so-called top kill, was tried and failed two months ago. The oil flow has been temporarily blocked since the installation of a new, tighter cap on July 15.
The permanent closure of the rupture can only be done through a parallel relief well, designed to intersect the original well shaft and allow injection of cement. This could happen as early as next week.
Federal scientists estimate that 4.9 million barrels of oil have gushed from the well - worth 400 million dollars at Tuesday's oil price. BP has collected about 800,000 barrels from the spill.
The accidental outflow exceeds a 1979 spill in Mexican waters to rank as the biggest ever.
BP has made a 20-billion-dollar commitment to the US government for cleanup and damage compensation.
The Mexican government is planning to sue BP for possible damage in its own waters, should any of the oil reach there, according to the newspaper Milenio, citing Mexico's Environmental Minister Juan Rafael Elvira Quesada. Mexico is seeking immediate payment of 70 million dollars for the indirect ecological damage.