BP ‘Fishing’ for Drill Pipe, Final Well Kill Delayed
HOUSTON, Texas, August 23, 2010 (ENS) – BP has gone “fishing” – reaching down nearly a mile below the surface of the Gulf of Mexico to remove a section of drill pipe that must come out of the Deepwater Horizon well before the failed blowout preventer can be retrieved.
Both drill pipe and blowout preventer, a complex set of valves atop the wellhead, will become evidence in investigations of the April 20 explosion that killed 11 crewmembers and resulted in the largest oil spill in U.S. history.
The well has been capped since July 15 and cemented in from the top. Sometime in September, BP plans to inject mud and cement in from the bottom, permanently sealing the troublesome well.
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Development Driller II and III at the Deepwater Horizon well site. (Photo courtesy U.S. Coast Guard) |
But before the final seal is placed, BP and government scientists and engineers have decided to retrieve the drill pipe and blowout preventer to improve their ability to handle the immense pressure they expect to build up when the mud and cement are pumped in from the bottom, the so-called “bottom kill.”
BP started fishing for the drill pipe early Saturday morning, after the success of a 48 hour pressure test assured engineers that the well is not going to leak oil if it is opened to the seafloor during the fishing and salvage operation.
Once the fishing operation has removed some 3,500 feet of drill pipe, and two much smaller sections of pipe, another blowout preventer unlatched from the on-scene rig Development Driller II will replace the one being brought up as evidence.
BP Vice President Kent Wells told reporters in a technical briefing Thursday, “A new blowout preventer gives us a much solider cap to the well. In that situation where we’ve sealed off the reservoir, we could have a lot of pressure on the top of the well. We’re comfortable handling that with a BOP, less so with just a capping stack.”
National Incident Commander retired Coast Guard Admiral Thad Allen authorized the fishing procedure and blowout preventer salvage in a directive late Friday night. It requires BP to submit for review and approval a procedure that ensures the salvage is performed “in a way that doesn’t compromise the investigation.” The letter also directs BP to ensure live feeds from remotely operated undersea vehicles are in place to document the removal and recovery process.
“The procedure should recognize and preserve the forensic and evidentiary value of the blowout-preventer stack,” Allen said in an email. “The procedure should also include measures to enable capture and removal of oil in the event of a release.”
At least 1,000 barrels of oil are still in the well, both BP and Allen have said. Recovering the drill pipe and replacing the preventer will delay the final sealing of the well by at least three weeks to mid-September, Allen told reporters Thursday.
The final seal will be put in place from a relief well that BP began drilling on May 2. The relief well drill bit now sits about 42 inches from the damaged well, and about 50 feet above the intersection point.
It has been held there pending a decision based on the consultations between the science team and the BP engineers regarding how we should handle the pressure related to the intersection when the mud goes into the annulus, said Allen.
Now, the “bottom kill” will probably take place after Septmber 6, he said. BP had planned to perform the operation around August 15.
Admiral Allen explained that the delay in implementing the bottom kill is the result of a cautious approach that to avoid worsening the situation.
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Neil Cramond, Gulf of Mexico marine authority for BP from the Deepwater Horizon rig, testifies at the joint investigation hearing, August 23, 2010. (Photo courtesy USCG) |
“We run the risk of forcing the seal up at the top of the well and having whatever material that was in the annulus, whether it’s hydrocarbon and/or mud enter the Deepwater Horizon blowout preventer in the capping stack and potentially exceeding the pressures in the stack and causing a discharge into the environment unless we could come up with some kind of device to relieve the pressure or move that stuff to the surface,” he said.
“The complexity associated with that and the risks associated with that and the timeline associated with that make that not the most favorable choice and we elected to move the blowout preventer in first before the bottom kill,” Allen said.
In addition to the Coast Guard and Interior Department, investigations into the disaster are being held by the Justice Department, the U.S. Chemical Safety and Hazard Investigation Board and several Congressional committees.
“All of us want to understand the causes of this incident so nothing like this ever happens again,” Wells said. “So our procedures will bring up the blowout preventer and the drill pipe and bring them to shore so we can see what went wrong.”
The fourth hearing of the Deepwater Horizon Joint Investigation Board opened this morning in Houston. It will cover well design and construction and the vessel safety management system.
A fifth hearing focused on an examination of the recovered drill pipe and blowout preventer will take place at a date to be announced. The Coast Guard and the Bureau of Ocean Energy Management, Regulation, and Enforcement are co-chairing the fact-finding investigation launched to determine the cause of the initial incident and fire.
Copyright Environment News Service (ENS) 2010. All rights reserved.
