http://www.nytimes.com/2010/05/09/us/09rig.html?scp=2&sq=oil%20spill&st=cse
A version of this article appeared in print on May 9, 2010, on page A1 of the New York edition.
New Setback in Attempt to Contain Gulf Oil Spill
Michael Appleton for The New York Times
Work continued on Saturday to stop a leaking oil well in the Gulf of Mexico.
By CAMPBELL ROBERTSON
Published: May 8, 2010
Readers’ Reports
As the oil spill reaches land, we would like your updates and photographs of what you’re seeing. Photos are optional but recommended.
Related
For BP, a History of Spills and Safety Lapses (May 9, 2010)
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Times Topic: Gulf of Mexico Oil Spill (2010)
Workers on Friday night maneuvered a containment dome — essentially a 98-ton steel box with an opening at the top — over the worst of two remaining leaks on the seabed to funnel the oil through a pipe to the surface, where it would be collected by a drill ship. With efforts to stop the leak by sealing the well at its source having proved unsuccessful, the dome was considered the most immediate way to limit the leak’s damage until the well is permanently closed.
But response crews discovered that the dome’s opening was becoming clogged with gas hydrates — crystal structures that form when gas and water mix and are found in the low temperature and high pressure at the ocean floor, officials said Saturday at a news conference here.
“I wouldn’t say it has failed yet,” said Doug Suttles, the operating officer for exploration and production for BP, the company that was leasing the oil rig when it exploded April 20. “What I would say is what we attempted to do last night didn’t work.”
The hydrates accumulated into a kind of slush that clogged the opening through which the oil was to be funneled to the surface.
That is only one of the problems presented by the hydrates, Mr. Suttles said. Since hydrates are lighter than water, a large accumulation threatened to increase the buoyancy of the dome and lift it out of place.
Unclogging the dome is not difficult. It can be done by lifting the dome to shallower waters, Mr. Suttles said.
For now, the dome has been moved 650 feet on the seafloor, where it will stay while officials spend “the next two or three days” deciding how to proceed, Mr. Suttles said. Every day is critical, considering 5,000 barrels of oil are pouring into the gulf daily, the National Oceanic and Atmospheric Administration estimates. Other experts say the flow is much greater, perhaps by an order of magnitude.
Last week, remotely controlled robots placed a specially designed valve over the end of a leaking drill pipe on the seafloor and stop oil from escaping at that point, though it did not change the overall amount flowing out.
The slick, which has already come ashore on the Chandeleur Islands off southeast Louisiana, is projected to curl west in the next three days, threatening not only the Mississippi River Delta but also miles of Louisiana coastline to the west of the river.
If the containment dome approach is not successful, other strategies will be explored. But the most dependable solution remains the digging of a nearby relief well, which would allow crews to plug the gushing cavity with heavy liquid.
Mr. Suttles said the drilling of such a well was already at 9,000 feet and proceeding ahead of plan. However, it is still months away from being in a position to stop the leak by intercepting the original well and pumping it full of concrete or other heavy liquid.
Meanwhile, the Obama administration was evaluating proposals for assistance in cleaning up the gulf from the United Nations and the European Union, as well as 14 individual countries, including Sweden, according to the State Department.
Michael Mohr, Sweden’s homeland security liaison at the embassy in Washington, said Saturday that officials in Stockholm were prepared to offer up to three skimming vessels able to collect about 50 tons of oil per hour from the sea and hold about 1,000 tons at a time. The ships could take several weeks to arrive from the Scandinavian peninsula, Mr. Mohr said. “We’re on standby,” he said.
Officials had emphasized for days the difficulty of successfully employing the containment dome. While domes have been used on leaks, they have never been used at such a depth, officials said. BP had anticipated the presence of hydrates, because the oil is mixing with seawater. Hydrates can form when methane bubbling out of the oil comes in contact with water, producing a cage of water molecules surrounding methane molecules.
To prevent that, officials had planned to circulate warm water around the pipe that connected the dome to the ship on the surface. But they had not expected hydrates to accumulate so quickly and at such high concentrations, effectively closing off the dome before the pipe was even attached. “The issue is how to keep them from forming again,” Mr. Suttles said.
BP is weighing several options, he said, including lowering the dome with the pipe attached or pumping methanol into the dome, which would prevent the formation of hydrates by acting as a sort of antifreeze.
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【出展リンク２】：
http://www.nytimes.com/2010/05/25/science/earth/25latest.html
The Latest on the Oil Spill
Published: May 24, 2010
THE NUMBERS It has been 34 days since the first explosion on the Deepwater Horizon rig. The spill’s impact on shore now stretches across 150 miles, from Dauphin Island, Ala., to Grand Isle, La., officials said.
GULF SPILL: READERS' REPORTSAs the oil spill reaches land, we would like your updates and photographs of what you’re seeing. Photos are optional but recommended.
Multimedia
Related
Oil Hits Home, Spreading Arc of Frustration (May 25, 2010)
Times Topic: Gulf of Mexico Oil Spill (2010)
THE MONEY The total cost to BP to date is about $760 million, or $22 million a day, compared with an initial estimate of $6 million a day last month, the company said.
PLUGGING THE WELL BP officials said the “top kill,” in which mud is pumped into the well, followed by cement, to overcome the pressure of the oil, will be tried Wednesday at the earliest. The method has never been tested 5,000 feet underwater. BP’s chief operating officer, Doug Suttles, said crews were working on a backup plan to fit a dome atop the well and then pump the oil to the surface.
SLOWING DOWN A mile-long tube operating for about a week has siphoned off more than half a million gallons, but it was collecting oil at a slower rate over the weekend. BP said that the siphon collected 47,040 gallons of oil on Sunday, 57,120 gallons on Saturday and 92,400 gallons on Friday.
OILY BIRD AIRLIFT Seven birds — three brown pelicans, two northern gannets and two laughing gulls — affected by the spill were transported by military aircraft from coastal Louisiana to Egmont Key National Wildlife Refuge in Florida and released there.
OBAMA CALL The White House released a photograph ofPresident Obama on the phone with Govs. Haley Barbourof Mississippi, Bobby Jindal of Louisiana, Charlie Crist of Florida and Bob Riley of Alabama on Monday. Also, at the president’s request, Energy Secretary Steven Chu postponed a trip to China and was to travel to Houston on Monday night to monitor the spill efforts.
NUMBER TO CALL Investigators urged anyone who finds debris from the Deepwater Horizon rig to leave it in place and call 202-309-9559.
MORE INFORMATION ONLINE An interactive map tracking the spill, live video of the leak and additional updates are available at
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【参考リンク】： oil spill 映像 ：
http://www.bp.com/liveassets/bp_internet/globalbp/globalbp_uk_english/homepage/STAGING/local_assets/bp_homepage/html/rov_stream.html
