BP finished pumping cement into its ruptured oil well in the Gulf of Mexico on Thursday to seal off the source of the world’s worst offshore spill, paving the way to permanently plug the blow-out later this month.

The day long cementing operation followed earlier injections of heavy drilling mud this week that had subdued the upward pressure of oil and gas inside the deep-sea Macondo well. The crippled wellhead was provisionally capped in mid-July. This is not the end, but it will virtually assure us that no oil will be leaking into the environment,” retired Coast Guard Admiral Thad Allen, who oversees the US oil spill response operation, said at a briefing in Washington.

“Monitoring of the well is under way in order to confirm the effectiveness of the procedure,” BP said in a statement announcing completion of the cementing work. The so-called “static kill” at the top of the well is due to be finished off with a “bottom kill” later in August with more mud and cement injected through a relief bore being drilled into the ruptured well shaft. This relief well is regarded as the final step in plugging the reservoir 13,000 feet (4,000 metres) beneath the seabed. “I will declare this well dead once we’ve intercepted the annulus (the space between the well pipe and surrounding rock) and we’ve assessed how much mud or cement we need to do from the bottom to finally kill this well,” Allen said.

Allen said BP would likely resume drilling the relief well 24 to 36 hours after the cementing was done, with the initial intercept expected within five to seven days after that. Progress in shutting off the cause of an environmental disaster for the US Gulf Coast came as a relief for both BP, whose image and stock took a beating, and US President Barack Obama, whose approval ratings suffered over criticism of his administration’s handling of the spill.

BP, which has lost over a third of its market value since the 20 April  blast that killed 11 workers, sank the Deepwater Horizon rig and triggered the spill, has said it would sell about US $30 billion in assets to cover costs related to the disaster.                                                                           Agencies

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