BP Plc will remove a failed blowout preventer from its ruptured Macondo well in the Gulf of Mexico under watchful eyes of investigators probing the deadly April 20 explosion.
Concern over how to safely proceed after pouring cement in the Macondo well from the top, as well as weather delays, pushed the last step past the U.S. Labor Day holiday on September 6 from mid-August, retired Coast Guard Admiral Thad Allen said at a briefing in Washington.
"As we get to the end, we are very close to putting this well away," Allen said. "I think none of us wants to make a mistake at this point."
Retired Coast Guard Admiral Thad Allen told BP to submit a removal plan in a directive issued late Friday and made public on Saturday after a 48-hour pressure test indicated the giant stack of pipes and valves could be removed and replaced with another with little likelihood of an oil leak.
The plan must say how BP will contain a leak if necessary, Allen said.
Allen said BP's plan will ensure investigators with the U.S. Department of Justice and a joint team of the Coast Guard and the U.S. Bureau of Ocean Energy Management have "unfettered access to observe and record the entire removal and recovery process" and retrieve the equipment once it is brought ashore.Meanwhile, Swiss-based Transocean Ltd, owner of the Deepwater Horizon rig that was under contract for BP when it exploded, has accused BP of withholding evidence about actions that led to the worst offshore oil spill in history.
That will include continuous live camera feeds of the removal by underwater robots with enough backups to ensure no interruptions, Allen said.
In a confidential letter to BP executives, Transocean said it "appears that BP is withholding evidence in an attempt to prevent any entity other than BP from investigating the cause of the April 20th incident and the resulting spill." (Right: Deepwater Horizon rig)
The blowout preventer is key evidence subpoenaed by federal investigators seeking the cause of the Deepwater Horizon explosion that killed 11 workers and unleashed the world's worst offshore oil spill.
BP said the letter contained "misguided and misleading assertions," and that the company has cooperated with ongoing federal investigations.
The blowout preventer failed when the well ruptured on April 20, causing an explosion aboard the drilling rig that killed 11 workers.
More than 4 million barrels of oil spewed into the Gulf, contaminating wetlands, fishing grounds and beaches from Louisiana to the Florida Panhandle. (Right: oil in marsh grass)
No oil has leaked into Gulf waters since July 15, when BP sealed shut a provisional cap over the wellhead.
The blowout preventer is key evidence in investigations of the disaster, including those by the U.S. Department of Justice and a joint probe by the Coast Guard and the U.S. Bureau of Ocean Energy Management.
"We do not want to have damage to that blowout preventer if we can avoid it because it's going to be material evidence of exactly what happened during the event itself," Allen said. (Left: Cmdr. Thad Allen at White House press briefing August 2nd)
In the meantime, BP is testing pressure in the well and seabed equipment, he said.
Kent Wells, BP's senior vice president of exploration and production, said later the test should confirm that the cement and a seal beneath the blowout preventer will hold in the 24-hour period it will take to remove it and install the replacement.
The relief well is about 50 feet from its target near the bottom of the Macondo well about 13,000 feet beneath the seabed.
BP engineers and government scientists were concerned cement injected from the top may have trapped up to 1,000 barrels of oil in the space between the well pipe and the surrounding rock layers.
They want to make sure pumping in mud and cement through the relief well will not increase pressure and force that oil up, where it could leak into the sea or damage the blowout preventer. (Left: image of oil spill size after oil flow stopped)
Wells said the replacement blowout preventer will be better than the failed one if the relief well intersection indeed increases pressure in the well.
"We just think it's a prudent thing to do going forward," Wells said.
Once another blowout preventer is installed on the well, BP said it will be able to resume drilling on a relief well to intersect the Macondo well to inject mud and cement and kill the leak for good. Allen said the intersect is expected sometime after the U.S. Labor Day holiday on September 6.
Reuters, "Final BP well plug delayed until September", accessed August 20, 2010
Reuters,"BP told to submit blowout preventer removal plan", accessed August 23, 2010