BP plans relief well to stem oil leak from Macondo well
BP PLC and Transocean Ltd. on Apr. 26 worked to activate a seafloor blowout preventer on the Macondo exploration well off Louisiana following an Apr. 20 explosion and fire on Transocean’s Deepwater Horizon semisubmersible rig.
This story was updated following a 3 p.m. news conference on Apr. 26.
OGJ Senior Staff Writer
HOUSTON, Apr. 26 -- BP PLC and Transocean Ltd. on Apr. 26 worked to activate a seafloor blowout preventer on the Macondo exploration well off Louisiana following an Apr. 20 explosion and fire on Transocean’s Deepwater Horizon semisubmersible rig.
The drilling rig Development Driller III was being moved into position to drill a well to intercept the Macondo well and inject a specialized heavy fluid to prevent flow of oil and gas. Workers then planned to permanently seal the original well.
The accident left 11 missing and presumed dead, authorities said late Apr. 23 as they discontinued search and rescue efforts after an extensive air and surface search covering 5,375 sq miles.
“Our deepest sympathies and prayers go out to the families of these 11 crew members,” said Rear Adm. Mary Landry, commander of the US Coast Guard 8th District. “Suspending a search is one of the most difficult decisions a commander has to make.”
Another 17 people were injured. The cause of the accident remains under investigation.
The Deepwater Horizon semi was drilling on contract for BP Exploration & Production Inc. about 52 miles southeast of Venice, La., in 4,992 ft of water near Rigel gas field. The exploration well had struck oil and associated gas at more than 18,000 ft TD.
Crews were running casing and cementing operations before the explosion and fire, Transocean and BP spokesmen said. On Apr. 22, Deepwater Horizon drilling rig sank. BP, Transocean, and USCG officials used remotely operated vehicles to monitor the wellhead on Mississippi Canyon Block 252.
The rig is resting on the ocean floor about 1,300 ft from the wellhead. A sheen on the surface as of Apr. 24 was estimated at 20 miles by 20 miles. Response officials estimate 1,000 b/d total is being released from two places with most of the oil coming from the end of the drill pipe. Oil also is leaking from the riser about 5 ft from the wellhead.
Attacking on two fronts
The Development Driller III was expected to arrive on Apr. 26. As of Apr. 25, the oil spill response team had recovered 1,143 bbl of an oily water mixture that was mostly water. Skimming vessels and vessels towing containment boom collected it.
“We are attacking this spill on two fronts—at the wellhead and on the surface offshore,” said BP Group Chief Executive Tony Hayward, who came to the Gulf Coast from London to meet with response personnel.
Dispersants were applied to the spill. Equipment available for the effort includes 32 marine vessels and 5 aircraft. A field operations response office was set up in Houma, La., where almost 500 people worked to coordinate the oil spill response.
BP said its team of operational and technical experts worked in coordination with several agencies, organizations and companies, including USCG, US Minerals Management Service, Louisiana Department of Environmental Quality, National Oceanic and Atmospheric Administration, US Fish and Wildlife Service, Louisiana Wildlife and Fisheries, and the Marine Spill Response Corp. (MSRC).
Steve Benz, MSRC president and chief executive officer, said the response to stemming the oil flow was the “largest response effort in MSRC’s 20-year history.”
“Given the current conditions and the massive size of our response, we are confident in our ability to tackle this spill offshore,” Hayward added.
Along with the response teams in action, additional people and equipment continue to arrive for staging throughout the gulf states in preparation for deployment should they be needed, authorities said.
Doug Suttles, BP’s chief operating officer of exploration and production, said the company’s main effort is to stop the oil flow through the blowout preventer (BOP) using four remotely operated vehicles.
A second plan is to drill one or two relief wells as needed. The MMS granted one permit already and is considering strategy from BP and Transocean that could involve granting more permits for a second relief well, said Lars Herbst, MMS Gulf of Mexico regional director.
A third effort involves designing and building a collection system that would involve a dome system on the seabed to contain any oil leaks. The collection system would include piping from the dome to transport the oil and gas to the surface.
“We don’t know which technique ultimately will be successful,” Suttles told reporters during a news conference. “We’re trying to activate the blowout preventer from the outside.”
Response teams are unable to determine current conditions within the blowout preventer, he said.
“I don’t believe any of us understand why this event occurred,” Suttles said. “We don’t know at this time what the blowout preventer did” at the time of the accident.
If workers are unable to get the oil under control through the BOP, Suttles estimates it will take at least 2 weeks to complete the engineering and fabrication of the dome collection system.
“This hasn’t been done in 5,000 ft of water before,” Suttles said of the collection system.
A relief well or wells would intercept the existing wellbore close to the original well’s 18,000 ft TD, he said. One drilling rig was scheduled to arrive on the scene on Apr. 26 and another rig was expected to arrive early next month.
Charlie Henry, a scientific support coordinator with the National Oceanic and Atmospheric Administration, said on Apr. 26 that he does not believe any oil will reach a shoreline for the next 3 days at least.
States on standby
State authorities in Louisiana, Alabama, and Mississippi are on standby with booms if needed to protect environmentally sensitive areas. The response team believes state authorities would have at least 3 days notice before any oil reaches the coast.
Meanwhile, authorities said the Ocean Endeavor rig owned by Diamond Offshore Drilling Inc. has been evacuated as a precaution. Ocean endeavor is 10 miles northeast of where the Deepwater Horizon had been working.
Henry said the US Fish and Wildlife Service spotted three whales, believed to be sperm whales, during a flyover in the vicinity of the oil sheen, which was estimated on Apr. 26 to cover 48 miles by 39 miles at its widest point. The use of dispersants was adjusted to avoid areas where the whales had been seen.
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