BP will undertake a critical test in the coming days that could determine whether it can fully seal off the ruptured oil well that has been gushing oil into the Gulf of Mexico for nearly three months, dpa reported.
The "integrity test" is designed to help determine whether the well at the bottom of the gulf is leaking from more than one place, and whether a new, tight-fitting cap placed on the wellhead late Monday could seal off the leak entirely.
The test was to begin late Tuesday and last up to 48 hours. Engineers plan to close valves on the so-called capping stack installation while carefully monitoring pressure readings.
"The higher the pressure the better," BP vice president Kent Wells said. A lower reading "means pressure is being released somewhere (else), and we don't know where."
If the test is successful, BP hoped the 5.5-metre, 68-ton cylinder newly installed atop the well could funnel all of the estimated 30,000 to 60,000 barrels of oil leaking daily up to tanker ships.
Even if the pressure readings are high, the solution is temporary. BP continues drilling a relief well that it hopes will intersect the existing well shaft at the end of this month, allowing a permanent closure of the well some time in August.
The leak has spewed massive undersea pollution since the Deepwater Horizon oil rig exploded on April 20, causing the biggest spill in US history as oil has washed up in nearby Louisiana and other states on the southern Gulf Coast.
Since April, a series of attempts by BP to contain the oil flow have failed, amid the complexity of capping a ruptured wellhead at unprecedented ocean depths of some 1.5 kilometres.