BP has done it. Finally, the British energy giant has managed to stop the flow of oil into the Gulf of Mexico. After 85 days and up to 184 million gallons, the company says it has temporarily halted the flow as it began key tests hoping to stem the spill for good.

Shortly after its engineers shut down the last of three valves on a giant new cap placed on the blown-out well at around 19:25 UTC on Thursday, a senior BP official confirmed that no oil was leaking into the sea.

The announcement was the first sign of real hope for desperate coastal residents who have had their livelihoods ravaged by the worst environmental disaster in US history.

Teeming fishing grounds have been closed and tourists have been scared away - two vital economic lifelines for the southern region still struggling to recover from the 2005 Hurricane Katrina.

Natural disaster
Endangered wildlife has also been increasingly threatened by huge ribbons of oil fouling the shores of the states of Texas, Louisiana, Mississippi, Alabama and Florida. The costly, massive clean-up is likely to last years.

US President Barack Obama, whose administration has led pressure on BP to stop the oil flow, welcomed the news of the capped well as "a positive sign," but cautioned: "We're still in the testing phase." He said he would address the issue again Friday.

The tests are intended to determine whether the well bore, which stretches four kilometers below the seabed, was damaged during the 20 April explosion on the BP-leased Deepwater Horizon rig, which sank two days later.

New leaks possible
BP is hoping to choke off the oil flow from the well, estimated at between 35,000 to 60,000 barrels a day. But doing so from the top could force oil out in new leaks if the well bore was damaged.

During the test, engineers will take multiple readings from the 30-foot (nine-meter)capping stack placed on top of the wellhead on Monday to monitor the pressure inside.

High pressure readings would allow the three valves to remain shut and the well would effectively be sealed, but low readings could mean there is a hole somewhere in the casing of the well where oil is escaping.

After 48 hours, the engineers will open up the system again and begin capturing the oil through two surface vessels to allow a new seismic survey to be carried out, said the official in charge of the US response, Coast Guard Admiral Thad Allen.

Final solution
A final solution to the leak is not expected before mid-August, when crews will complete the first of two relief wells, allowing the oil reservoir to be permanently plugged in a "kill" operation.

The Gulf disaster has so far cost BP some 2.78 billion euros and compensation claims from devastated residents of the region could reach 10 times that.

Local officials who have seen their coasts sullied by the oil were cautious but hopeful.

Meanwhile the Financial Times reported Friday that BP is speeding up the sale of up to 15.5 billion euros of assets in a bid to boost funds after the Gulf oil spill. BP is seeking to build up a disaster fund of 20 billion dollars to cover the clean-up costs for the disastrous oil spill.

Source: AFP/Reuters