More tests needed on BP's capped oil well

BP Plc's blown-out Gulf of Mexico well appeared strong enough to keep oil from leaking on Saturday, but officials said tests could be extended beyond 48 hours as pressure in the well was rising more slowly than they had hoped.

BP began pressure tests on the Macondo well after a new cap choked off the flow of oil into the Gulf on Thursday for the first time since the April 20 rig explosion of the rig.

The tests are intended to show whether the blowout 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, said Kent Wells, BP senior vice president of exploration and production. 

But the tests could last beyond the original 48-hour deadline set for Saturday afternoon because pressure was rising very slowly, Wells said. Increased pressure would indicate the oil was being contained in the well.

Once tests are 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.

Retired Coast Guard Admiral Thad Allen, the US government's point man on the spill, has final say on when the test will end and BP's next course of action, Wells said. 

About 41 hours into the test on Saturday morning, pressure had reached 6,745 pounds per square inch and was rising about 2 psi per hour, Wells said. 

Allen and BP want pressure to hit and sustain 7,500 psi or more, which would indicate all the oil and gas was flowing to the top with no breaches. Pressure beneath 6,000 psi would indicate a possible leak.

BP was told to step up monitoring with undersea robots for any breaches and gather additional seismic data to detect any pockets of oil in the layers of rock and sediment around the well, Allen said on Friday.

US president Barack Obama warned on Friday that more work was needed before the well could be considered fixed.

"We won't be done until we actually know that we've killed the well and that we have a permanent solution in place. We're moving in that direction, but I don't want us to get too far ahead of ourselves," Obama said at the White House.

Obama is under fire to push BP to permanently plug the leak and clean up an environmental and economic mess across all five states along the Gulf of Mexico. The spill, the worst in US history, has cut into multi-billion dollar fishing, tourism and drilling industries.

Under pressure from Obama, BP has established a $20-billion fund to cover damage claims from the spill. 

The crisis has also complicated US 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 with negotiating the release of a Libyan man convicted of the 1988 Lockerbie airline bombing.

The US 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.

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.

US 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. 

BP still expects to drill a new well by early August to intersect the ruptured one and seal it with mud and cement.

Investors remained cautious on BP's latest effort, however, as several previous attempts failed to plug the leak caused by the explosion that killed 11 men.

Shares in the company, which fell about 50% in the first two months of the crisis but have gained 40% since late June, were down nearly 5% on Friday as part of a broader sell-off on the New York Stock Exchange.

Estimates vary widely of BP's total costs -- from $40 billion to $100 billion -- which will run on for many years as lawsuits wind their way through courts.

Investors welcomed reports that BP was moving closer to sealing the first deal in its planned $10 billion of non-core divestments to help pay cleanup costs.

The company and bankers were finalizing details of the asset sales, including some US interests to Apache Corp, said CNBC and the Financial Times.