BP began sealing its runaway oil well in the Gulf of Mexico with cement yesterday, one of the final steps to plug the gusher at the centre of the worst US environmental disaster on record.
Some 15 weeks after the well ruptured and 21 days after the flow was stemmed with a temporary cap, the massive slick which once stretched for hundreds of miles is rapidly disappearing from the Gulf.
But officials cautioned that a great deal of clean-up work remained and that the long-term impact of the disaster could be felt for years, even decades.
In a long-awaited breakthrough, BP brought the well under control Wednesday after pumping heavy drilling fluid into the busted Macondo well for eight hours, forcing the oil back down into the reservoir miles beneath the seabed.
The British energy giant then began pumping cement after the procedure was approved by US officials. In giving the green light, spill response chief Thad Allen emphasised that the cementing should “in no way delay the completion of the relief well,” expected to be finished in mid-August to seal the well permanently.
“So, the long battle to stop the leak and contain the oil is finally close to coming to an end. And we are very pleased with that,” President Barack Obama said. “Our recovery efforts, though, will continue. We have to reverse the damage that’s been done.”
BP senior vice president Kent Wells expressed relief that 20 days after the flow of oil in the sea was stemmed with a temporary cap “it’s very difficult for us to find any oil anywhere on the surface.”
He refused, however, to declare victory until the well is permanently sealed.
It took 106 days to shut the well down in the wake of a devastating explosion on April 20 that killed 11 workers and sank the BP-leased Deepwater Horizon rig, unleashing a torrent of oil into the Gulf.
At 4.9 million barrels – or enough oil to fill 311 Olympic-sized swimming pools – the disaster is the biggest maritime spill on record.
It threatened the fish and wildlife-rich US Gulf coast with environmental ruin and plunged residents of coastal communities into months of anguish over their livelihoods and the region’s future.
A government report released Wednesday found that a third of the oil was captured or mitigated through burning, skimming, chemical dispersion and direct recovery from the wellhead.
Heat from the sun helped some of the chemicals in the crude evaporate. Waves and currents broke the slick up into smaller patches. Then the microbes which feed on natural oil seeping in the Gulf got to work, it said.