BP restarts oil capture after ship fire

HOUSTON (Reuters) - BP Plc restarted its Gulf of Mexico oil-capture system on Tuesday nearly five hours after a small fire on the vessel capturing the crude prompted a shutdown.

During the shutdown, oil gushed unchecked from the company's ruptured well.

The fire at the top of the derrick on Transocean Ltd's Discoverer Enterprise drillship was quickly extinguished, and no one was hurt, BP said.

Shortly after BP and the U.S. Coast Guard confirmed the restart, a team of U.S. scientists significantly revised its estimate of the "most likely flow rate of oil today" to 35,000 to 60,000 barrels (1.47 million gallons to 2.5 million gallons/5.56 million liters to 9.5 million liters) a day.

The estimated range includes the oil being captured.

That team initially estimated the leak to range from 12,000 to 19,000 barrels per day, and last week increased that to 20,000 to 40,000 barrels per day.

The latest estimate "represents a significant step forward in our effort to put a number on the oil that is escaping from BP's well," U.S. Energy Secretary Steven Chu said in a statement.

Chu said the revised estimate stems from data gathered from pressure meters that were placed on a containment cap corralling some of the oil at the seabed last weekend.

He said the 60,000 barrel-per-day figure is "less certain," but the need to be ready for the worst is "why we are continuing to focus on responding to the upper end of the estimate."

The containment system has been capturing more than 15,000 barrels a day for a week. BP didn't say how much it was capturing upon the restart, but the system surpassed 15,000 barrels a day on its fifth day of operation.

BP said on its website that the system collected 5,610 barrels of oil during the first 12 hours of Tuesday, which reflected the shutdown. The system had been collecting more than 7,000 barrels every 12 hours.

The Enterprise can process a maximum of 18,000 barrels a day, though BP initially said it could handle up to 15,000 barrels a day. One barrel equals 42 U.S. gallons (160 liters).

The company announced the fire and shutdown minutes after Lamar McKay, president of BP America, the company's U.S. operations, emerged from a lengthy hearing in Washington of the U.S. House of Representatives subcommittee on energy and environment where he testified with other top executives of major oil companies.

LIGHTNING STRIKE

BP spokesman Robert Wine said BP suspects a lightning strike ignited vapors escaping from a vent pipe connected to storage tanks holding captured oil on the drillship.

The company also said in its update on oil collection for the first 12 hours of Tuesday that a faulty sensor caused another 30-minute shutdown.

BP had aimed to start up a second containment system that would increase surface oil-handling capacity to 28,000 barrels a day. Hours before the shutdown was publicly known, McKay told the committee that the second system would "hopefully" would be working on Tuesday.

That system would increase BP's capacity to handle oil siphoned from the deep-sea well to up to 28,000 barrels a day, according to BP.

The increase is part of an overall plan to raise that capacity to 80,000 barrels a day by mid-July, according to BP's plan submitted to the U.S. Coast Guard late on Sunday.

"We will have a vessel called the Helix Q4000 on location and working hopefully today (Tuesday) that will be burning oil that is produced up to that vessel," McKay said at the hearing.

The current system involves a containment cap on top of BP's failed blowout preventer equipment at the seabed that channels oil through a fixed pipe to the Enterprise a mile above, according to BP.

A drillship is a vessel equipped with a drilling rig that can stay in place for long periods while drilling, testing and completing offshore wells.

The system doesn't capture everything. A live video feed of the cap has consistently shown an undetermined amount of oil gushing out from under the cap and from three open vents on top of it. McKay told the congressional panel the current system's capacity "is lower than the total rate of the well."

"Today we should have a secondary system producing off that blowout preventer that may relieve some of that that's coming out," McKay told the lawmakers.

OIL EXECUTIVES TESTIFY

McKay appeared before the subcommittee with top executives from Exxon Mobil Corp, Chevron Corp, ConocoPhillips and Royal Dutch Shell who defended their drilling practices in the wake of the disaster.

BP will try to collect the spewing oil until a pair of relief wells now being drilled help to permanently plug the well in August, according to BP.

The Q4000 is a service rig intended to siphon up to 10,000 barrels a day from a hose connected to the blowout preventer, bringing the total oil-handling capacity to 28,000 barrels a day, according to BP.

The company originally planned to use other vessels and systems to expand that capacity to up to 50,000 barrels (2.1 million gallons/7.95 million liters) a day by mid-July.

The Coast Guard has demanded that BP work faster and that more collection capacity be added.

BP's overall new plan, submitted to the Coast Guard late Sunday, proposes adding 50,000 barrels a day of capacity by the end of June, and another 30,000 barrels per day by mid-July.

BP used the Q4000 system and accompanying seabed equipment installed last month for its failed "top kill" effort to smother the leak. The top kill involved pumping heavy fluids into the well.

Now BP intends to reverse course, using the series of hoses and pipes to pull oil from the well to a service rig on the surface. The rig lacks processing or storage capability, so oil collected there will be burned off, BP said.

(Reporting by Kristen Hays, Editing by Sandra Maler)