BP will extended critical tests on the leaking MC252 Well in the Gulf of Mexico for another 24 hours even though it appears to have capped the huge oil leak, the top US official overseeing the spill response said on Saturday, Reuters reported.
The British energy giant, which cut off the flow of oil from the deep-sea well on Thursday when it began the test to gauge its structural integrity, expressed growing confidence that the well was intact.
“As we continue to see success in the temporary halt of oil from the leak, the US government and BP have agreed to allow the well integrity test to continue another 24 hours,” retired Coast Guard Admiral Thad Allen, the US government’s point man on the spill, said in a statement.
Kent Wells, BP’s senior vice president of exploration and production said pressure in the well was rising more slowly than hoped. Pressure reached 6,745 pounds per square inch (psi) on Saturday morning and was rising about 2 psi per hour, he said.
Allen and BP have said they want pressure to hit and sustain 7,500 psi or more, which would indicate oil and gas was flowing to the top with no breaches.
The higher pressure would indicate the well could hold back all the oil flow if ships siphoning off the crude had to disconnect and move away in advance of a hurricane. Pressure beneath 6,000 psi would indicate a possible leak, officials said.
Once the test is complete, BP plans to siphon up to 80,000 barrels (12.7 million litres) of oil a day and send it to waiting ships on the sea surface.
Allen has final say on when the test will end and BP’s next course of action, Wells said. Allen said that when the test is stopped, BP will immediately start up two oil-capture vessels on the surface to siphon crude from the well.Officials are monitoring the pressure in the well, which extends 2.5 miles (4 km) under the seabed, to judge whether it is structurally sound with no seabed leaks. Allen’s statement did not provide pressure readings as of Saturday afternoon.
The ongoing test is intended to show whether the April explosion 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.
It had been due to last two days and end Saturday.Â
Wells said there was no evidence of any leaks. “We’re feeling more comfortable that we have integrity” in the well, Wells added.  He also said BP was checking into bubbles coming out of a valve on piping at the very top of the well, which he called “quite normal” and could be nitrogen rather than natural gas leaking from below.
Shutting the gushing oil well with a tighter-fitting containment cap marks the first time that it has stopped since the April 20 rig explosion which killed 11 workers triggered the disaster.
Even if test ends successfully, officials have said the only permanent fix is a relief well BP has been drilling to intersect the ruptured well under the seabed and seal it with mud and cement next month. Having a structurally intact well would boost that effort.
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