BP extended for another 24 hours a critical test of its blown-out Gulf of Mexico well that so far has shut off the huge oil leak, the top US official overseeing the spill response has said.
The British energy giant, which cut off the flow of oil from the deep-sea well on Thursday when it began the test to gauge its structural integrity, expressed growing confidence that the well was intact.
Kent Wells, BP's senior vice president of exploration and production, said there was no evidence of any leaks. "We're feeling more comfortable that we have integrity" in the well, Mr Wells added, in what would be an important step toward permanently plugging it.
When BP choked off the flow of oil on Thursday using a new, tight-fitting containment cap installed atop the well a mile (1.6 km) under the ocean surface, it marked the first time the gusher had stopped since the April 20th offshore rig explosion that killed 11 workers and triggered the disaster.
US government officials say that as soon as the test is completed, BP will reattach pipes to the capping equipment and resume siphoning oil to ships on the surface. Officials have said that virtually all the oil from the ruptured well can be captured that way until it can be permanently plugged with a relief well, as planned, in August.
The massive oil spill has caused an economic and environmental disaster along the US Gulf Coast.
"As we continue to see success in the temporary halt of oil from the leak, the U.S. government and BP have agreed to allow the well integrity test to continue another 24 hours," retired Coast Guard Admiral Thad Allen, the US government's point-man on the spill, said in a statement.
Officials are monitoring the pressure in the well, which extends 2.5 miles (4 km) under the seabed, to judge whether it is structurally sound with no seabed leaks. Mr Allen's statement did not provide pressure readings as of yesterday afternoon.
The ongoing test is intended to show whether the April explosion damaged the piping and cement inside the well, which could allow oil and gas to leak out the sides and seep up through the seabed.
It had been due to last two days and end Saturday. Mr Allen's statement indicates it will continue through this afternoon.
Wells said BP was checking into bubbles coming out of a valve on piping at the very top of the well, which he called "quite normal" and could be nitrogen rather than natural gas leaking from below.
President Barack Obama, whose US public approval ratings slipped as the oil spill crisis dragged on, has welcomed the capping of the well but cautioned that there is much work to be done before a permanent solution is achieved.
Even if test ends successfully, officials have said the only permanent fix is a relief well BP has been drilling to intersect the ruptured well under the seabed and seal it with mud and cement next month. Having a structurally intact well would boost that effort.
Mr Obama has been under fire to push London-based BP to plug the leak and clean up an environmental and economic mess in all five states on the Gulf of Mexico. The spill, the worst in U.S. history, has ravaged multibillion-dollar fishing, tourism and drilling industries and soiled hundreds of miles of seashore.
Mr Wells said pressure in the well was rising more slowly than hoped. Pressure reached 6,745 pounds per square inch (psi) yesterday morning and was rising about 2 psi per hour, he said.
Mr Allen and BP have said they want pressure to hit and sustain 7,500 psi or more, which would indicate oil and gas was flowing to the top with no breaches.
The higher pressure would indicate the well could hold back all the oil flow if ships siphoning off the crude had to disconnect and move away in advance of a hurricane. Pressure beneath 6,000 psi would indicate a possible leak, officials said.
Once the test is complete, BP plans to siphon up to 80,000 barrels (12.7 million liters) of oil a day and send it to waiting ships on the sea surface.
Mr Allen has final say on when the test will end and BP's next course of action, Wells said. Allen said that when the test is stopped, BP will immediately start up two oil-capture vessels on the surface to siphon crude from the well.
The oil spill crisis continues to complicate US relations with close ally Britain. British prime minister David Cameron is set to meet Mr Obama on Tuesday.
Britain's foreign secretary William Hague said in a letter to US secretary of state Hillary Clinton on Saturday "there is no evidence that corroborates in any way the allegations of BP involvement" in Scotland's release last year of a Libyan man convicted of the 1988 bombing of a US airliner over Scotland.
The US Senate Foreign Relations Committee has scheduled a July 29th hearing on possible ties between BP and the release by Scotland of Abdel Abdel Basset al-Megrahi, a Libyan intelligence officer who was the only person convicted of the Pan Am Flight 103 bombing over Lockerbie, Scotland. The Lockerbie bombing killed 270 people, most of them Americans.
The Foreign Relations Committee plans to ask BP officials to testify about the matter after the company said it had lobbied the British government in 2007 to speed up a prisoner transfer agreement with Libya.
Many Britons have expressed the view that the United States is treating BP too harshly to the detriment of British pension funds and other investors who have big stakes in the company.
Last month BP, under pressure from Mr Obama, agreed to create a $20 billion fund to cover damage claims from the spill.
Estimates vary widely on BP's total costs - from $40 billion to $100 billion - which will run on for many years as lawsuits wind their way through courts.
Reuters