BP Oil Leak Halted During Test

For the first time since the blowout nearly three months ago, no oil from the Deepwater Horizon well is escaping into the Gulf of Mexico. The well has been closed since 2:25 p.m. CDT, marking the start of a critically important test of the well's integrity but not necessarily the end of the spill, BP Senior Vice President Kent Wells told reporters at an afternoon briefing.

The ongoing integrity test is expected to continue for between six hours and two days, during which time the oil pressure in the well will be measured and evaluated. If the well is structurally sound, the pressure within it should rise and hold at a high level. Low or decreasing pressure readings, on the other hand, would suggest that there is underground damage to the well's casing, allowing oil to escape and percolate into the surrounding rock. In a worst-case scenario, any escaping oil could make its way to the surface and start an uncontrollable leak elsewhere on the seafloor.

To minimize the risk of further damaging the well or causing a separate leak, the test will be halted at the first sign of evidence that the well isn't holding pressure. In that case, the valves on the cap would be reopened, allowing oil to flow once more.

According to Wells, BP will be consulting with a team of industry and government experts every 6 hours to assess the results and decide whether the test should continue. If the test is halted, containment operations capable of funneling at least 22,500 barrels of oil per day to the surface would resume, and BP says it would eventually, over the next few weeks, have the capacity to capture all or most of the flow (currently estimated at 35,000 to 60,000 barrels per day).

"It felt very good not to see any oil flowing into the Gulf of Mexico," Wells said, noting that the test will be a success no matter what the outcome. Even if it shows that the well casing has been compromised, it will provide a much-needed assessment of the integrity of the well. "We need to have the test move forward, we need to learn from it and make the right decision [as to future containment operations]."