By Kristen Hays and Eric Onstad
LONDON/HOUSTON (Reuters) - BP <:BP.LO:>s shares rose on Friday on hopes that it has at last capped the ruptured subsea well that has been spewing oil into the Gulf of Mexico for the past three months and can now begin the clean-up.
BP finally choked off the leak on Thursday, the first time it has managed to cap the flow since the blowout on April 20 which has caused the worst offshore oil spill in U.S. history and an environmental disaster for the U.S. Gulf coast region.
Investors welcomed the news that the leak has been capped but remained cautious since BP needs to complete 48 hours of tests on whether the well will remain intact after a new tight-sealing containment cap was installed on the mile-deep subsea wellhead three days earlier.
Estimates vary widely of BP's total costs, which will run on for many years as lawsuits wind their way through courts.
Three analysts surveyed by Reuters Insider television forecast BP will spend between $63 billion (40 billion pounds) to $100 billion over the next 15 years in fines, cleanup costs and legal costs while analyst Peter Hutton at NCB Securities in London pegs total costs at $40 billion.
"It's relief all around to see that (undersea) camera with no oil coming out," said Hutton. "But people recognise that they're not completely out of the woods."
BP's shares in London bounced to a six-week high, gaining 4 percent to 417 pence at 1237 GMT after the U.S. shares closed up 7.6 percent on Thursday.
The battered shares more than halved in value during the first two months of the crisis, but have bounced by more than 40 percent since touching a low in late June. About $65 billion has been wiped off BP's market value since the rig explosion that killed 11 workers in April.
ASSET SALES
Investors also welcomed reports that BP was moving closer to sealing the first deal in its planned $10 billion of non-core divestments to help pay for clean-up costs.
The company and bankers were finalising details of the sales of assets, including some U.S. interests to Apache Corp, said CNBC and the Financial Times.
The good news about halting the flow of oil into the Gulf was tempered by concern about BP's future in the United States.
The U.S. Senate Foreign Relations Committee said it had scheduled a hearing on July 29 into BP's actions in connection with last year's release of a Libyan convicted for the 1988 bombing of an airliner over Lockerbie.
BP also faced new measures in the U.S. Congress. Lawmakers are considering a range of new rules that could require tougher safety regulations on offshore drilling or bar companies like BP from new offshore exploration leases.
POSITIVE SIGN
BP, which has failed several times in its efforts to end the leak, managed to stop the flow of oil as it conducted a test in which it closed valves and vents on the containment cap.
"I think that it is a positive sign," said U.S. President Barack Obama, whose public approval ratings fell as the oil spill crisis dragged on. He cautioned that "we're still in the testing phase."
"The well test is continuing. It's going to be reviewed every six hours and the decisions with the government authorities will be taken at each of those six-hour stages to see whether we're pleased with the results," BP spokesman in London Robert Wine said on Friday morning.
The test, which could last up to 48 hours, gauges pressure in the well to assess its condition. Officials said the test would show whether the cap can safely shut off the flow from the well if oil-capture vessels at the surface must disconnect, for example in the event of a hurricane.
"We're encouraged by this development, but this isn't over," said retired Coast Guard Admiral Thad Allen, the U.S. government's point man on the spill.
The Coast Guard said BP is likely to release the flow of oil again after the test is done -- siphoning it to ships on the ocean surface in an improved system able to handle up to 80,000 barrels a day until it can seal the well permanently.
That should be more than enough to capture the whole well output, as estimates put the spill rate at between 35,000 barrels (1.47 million gallons/5.56 million litres) and 60,000 barrels (2.5 million gallons/9.5 million litres) a day.
The British energy giant still expects to complete drilling a new well by early August to intersect the ruptured well -- which extends 2.5 miles (4 km) under the seabed -- and seal it with mud and cement.
The leak has soiled hundreds of miles (km) of shoreline, shut down about a third of Gulf fisheries and hurt tourism and fishing in all five U.S. Gulf states. It has also created problems for Obama as the government works to respond to the crisis while area residents struggle financially.
The news that BP had at last stopped the leak gave fresh hope to battered coastal communities.
"I tell you what, we needed that," said Jimmy Thibodaux, a resident of the small southern Louisiana town of Cut Off.
(Additional reporting by Chris Baltimore in Houston and Alexandria Sage in Cut Off, Louisiana; Writing by Eric Onstad and Ed Stoddard; Editing by Will Dunham, Greg Mahlich)
