BP to conduct test to show if Gulf well dead

BP Plc will conduct a pressure test on its ruptured Gulf of Mexico oil well late on Saturday to make sure that cement pumped into the bottom killed it for good, the company said.

The test is the last step toward declaring the well dead and closing the seabed chapter of the worst oil spill in US history. The disaster began nearly five months ago with a blowout and explosion that killed 11 men and sank a drilling rig. No announcement declaring the well dead is expected until Sunday.

BP faces years of litigation, multiple investigations and the daunting job of repairing its tattered image in the United States, where the London-based oil giant conducts 40 percent of its business. That includes the Gulf, where BP is the largest producer.

The blown-out Macondo well spewed more than 4 million barrels of oil into the Gulf before BP sealed it shut with a cap on the wellhead on July 15. The spill damaged coastlines along the US Gulf Coast, killing wildlife and hurting the livelihood of fishermen and others.

BP pumped cement into the well from the top on August 5. Repeating that procedure at the bottom through a relief well has long been considered the final assurance the well is dead.

The relief well intercepted the Macondo well late on Thursday near its bottom about 13,000 feet (4,000 metres) beneath the seabed. On Friday, BP pumped in cement for seven hours and waited for it to finish curing on Saturday before conducting the final test.

Retired Coast Guard Admiral Thad Allen said last week that if the test showed the reservoir was completely sealed off from the well and no oil could flow upward, he would declare the Macondo well dead.