BP Plc expressed growing confidence on Saturday that its blown-out Gulf of Mexico well was effectively sealed, but a pressure test was likely to be extended to ensure there were no seabed leaks, according to Reuters BP started a pressure test on the well on Thursday after a new cap it had attached choked off the flow of oil into the Gulf. That was the first time the gusher had been stopped since the April 20 rig explosion that killed 11 workers and started the leak. The test passed a 48-hour deadline on Saturday afternoon with no hint from BP of a stopping point. It was intended to show whether the 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. "We're feeling more comfortable that we have integrity" of the well, Kent Wells, BP senior vice president of exploration and production, said before the deadline. U.S. President Barack Obama welcomed the capping of the well on Friday but warned there was much work to be done before a permanent solution was in place. Obama is under fire to push London-based BP to plug the leak and clean up an environmental and economic mess across all five states on the Gulf of Mexico. The spill, the worst in U.S. history, has cut into multibillion-dollar fishing, tourism and drilling industries and wreaked havoc on the environment. Wells said the test could be extended because pressure was rising more slowly than hoped. Pressure had reached 6,745 pounds per square inch on Saturday morning and was rising about 2 psi per hour, Wells said. Retired Coast Guard Admiral Thad Allen, the U.S. official overseeing response to the spill, and BP 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. Increased 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. 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 a mile (1.6 km) up to waiting ships. Allen has final say on when the test will end and BP's next course of action, Wells said. Even if test ends successfully, 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. CAMERON COMING TO WHITE HOUSE The 3-month-old crisis has complicated U.S. relations with close ally Britain. British Prime Minister David Cameron is set to visit the White House on Tuesday amid a simmering controversy over BP's possible involvement in negotiating the release of a Libyan man convicted of the 1988 bombing of a U.S. passenger jet over Lockerbie, Scotland. The U.S. Senate Foreign Relations Committee plans to ask BP officials to testify after the company said it had lobbied the British government in 2007 over a prisoner transfer agreement with Libya. Cameron said on Friday he would stress how important a "strong and stable" company is to both nations. On Saturday, Britain's foreign secretary, William Hague, said in a letter to U.S. Secretary of State Hillary Clinton there was no evidence BP had any connection to the release of the Lockerbie bomber. Many Britons believe Washington is treating BP too harshly, to the detriment of British pension funds and other investors who have big stakes in the company. U.S. lawmakers also are considering a range of new rules that could impose tougher safety regulations on offshore drilling or bar companies like BP from new offshore exploration leases. Debate is set to step up this week as Congress is slated to debate an energy bill. Last month Obama persuaded BP to establish a $20 billion fund to cover damage claims from the spill. COSTS BP still expects to drill a new well by early August to intersect the ruptured one and seal it with cement. Investors remained cautious on BP's latest effort, however, as several previous attempts failed to plug the leak. 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. Local residents worried that fierce storms, which often plague the region in the summer, could complicate efforts. "I think Mother Nature will take care of it eventually," Philip Simmons of Empire, Louisiana, said of the cleanup. "But if you get a hurricane or really bad weather then we're really in trouble."
