Posted on Mon, Aug. 30, 2010
last updated: March 15, 2013 11:58:33 AM
WASHINGTON — High seas at the site of BP's Deepwater Horizon oil well in the Gulf of Mexico will delay for at least two to three days the recovery of the well's failed blowout preventer, Retired Coast Guard Adm. Thad Allen said Monday.
The weather also will push back the completion of a relief well that Allen has said for months is the only way to ensure that the Deepwater Horizon well is sealed permanently.
Engineers had hoped to lift the blowout preventer either Monday or Tuesday and install a new blowout preventer over the well on Wednesday in preparation for resuming drilling on the relief well perhaps Sept. 7 or 8. An effort to intercept the Deepwater Horizon wellbore with the relief well might have come as soon as four days after that.
With weather delaying those steps, however, it now appears likely that the relief well won't reach the Deepwater Horizon well before mid September — a reminder of how critical BP's successful closing off of the well July 15 with a containment valve known as a capping stack has been in easing the sense of crisis.
No oil has spewed into the Gulf since the capping stack's valves were closed 46 days ago. Had the capping stack not worked, however, oil still would have been gushing from the well at an estimated rate of 53,000 barrels per day. That would have added at least 2.4 million barrels to the 4.9 million barrels government scientists have estimated spewed from the well between April 20 and July 15.
Allen, briefing reporters by phone from the Development Driller III rig at the site 48 miles off the Lousiana coast, said Monday that waves at the well site were six to eight feet tall, too high for surface ships to lift the blowout preventer safely. Of primary concern, Allen said, was that the rising and falling of the waves would cause too much force to be exerted on the blowout preventer as it was tugged from the seafloor.
Allen said last week that engineers are uncertain whether the blowout preventer, a four-story collection of gears and valves that weighs hundreds of thousands of pounds, is still connected to drilling pipe below the seafloor. Concerned that lifting the blowout preventer could damage cement that is now sealing the well, engineers had decided to limit the amount of pressure they'd exert on the device to 80,000 pounds until they were certain how or if the blowout preventer is connected to pipe still in the well. A wave, however, could suddenly add to that pressure.
Allen said the wave action also could cause the blowout preventer, once freed from the seafloor, to swing like a pendelum while it was suspended in the water 5,000 feet below the surface.
Allen said technicians were prepared to move ahead quickly once the weather calmed. Pipes and hoses that had tied the blowout preventer to equipment on the seafloor and ships on the surface were all disconnected over the weekend in preparation for the device's recovery.
Why the blowout preventer, which is designed to sever the drill pipe leading from the well to the surface, failed is a key question in the investigations of the Deepwater Horizon catastrophe, which killed 11 oilrig workers and caused billions of dollars in economic damages. BP and Transcocean, which BP hired to drill the well and owns the blowout preventer, have blamed each other for its failure.
Allen said a 11 members of a Justice Department evidence team that will supervise the blowout preventer's recovery are aboard the Discoverer Enterprise drill ship, which will haul the capping stack to the surface, and the Q4000 drilling platform, which will bring the blowout preventer to the surface.