BP Plc is evaluating data from a pressure test it began yesterday that will determine whether its leaking Gulf of Mexico oil well can remain sealed.
By shutting off valves in a cap bolted to the top of the Macondo well this week, BP stopped the flow of oil for the first time in almost three months.
“It felt very good not to see any oil going into the Gulf of Mexico,” BP Senior Vice President Kent Wells told reporters on a conference call yesterday. “We’re very encouraged.”
National Incident Commander Thad Allen said in a statement it “remains likely” that BP will have to reopen the flow of oil from the well and collect as much as 80,000 barrels of oil a day until the well can be permanently plugged.
“This isn’t over,” Allen said.
The test is measuring the pressure inside the well, and may continue for as long as 48 hours, BP said in an e-mailed statement yesterday.
The disaster, the biggest oil spill in U.S. history, followed an April 20 explosion aboard the Deepwater Horizon drilling rig. The well has been spewing 35,000 to 60,000 barrels of oil a day, according to a U.S. government-led panel of scientists.
BP’s confirmation that it had stopped the flow from the well pushed the London-based oil company’s U.S. shares up 7.6 percent to $38.92, the highest value in more than a month.
Success in stopping the leak, even temporarily, “has the market excited that this could lead to an earlier-than-expected containment of the well, from expectations of mid-August to within the next several days,” Brian Gibbons, an analyst at CreditSights Inc. in New York, said in an interview.
If BP detects lower pressures, it may stop the test sooner and resume recovering as much oil as possible through pipelines leading from the well to vessels on the surface of the Gulf, Allen said in a New Orleans press conference. Lower pressures indicate a leak has erupted elsewhere and the flow will continue until the well is plugged, said BP officials.
Higher pressure between 8,000 and 9,000 pounds per square inch will show the oil is trapped in the wellbore drilled by the Deepwater Horizon, an encouraging sign the well might be successfully sealed with the cap.
Being able to shut in the oil would help in the event a hurricane entered the Gulf before BP permanently plugs the well, Allen said.
If the well withstands high pressure for two days, BP will reopen the valves, let the pressure drop, and run a seismic survey to check for any leaks before shutting the valves for good, Allen said.
“I would prefer that the pressure test goes well, that it holds pressure,” said Philip Adams, an analyst at Gimme Credit LLC in Chicago. “And that they are in fact able to say that there has not been damage to the wellbore below the seafloor.”
The pressure test was delayed after the government raised concerns it might cause the well to burst open beneath the seabed. After getting necessary approvals, BP halted the test July 13 because a leak developed when it began shutting off the flow to allow pressure to build up.
Sealing the leak using the new cap is an interim step before BP can permanently plug the well with cement, Allen said.
“The number-one goal is to shut in the well and kill it and stop it at the source,” Allen said yesterday.
The first of two relief wells being drilled to plug the well is about 100 feet (30 meters) from intercepting the leak, Allen said.
BP had been sending captured oil from the well to the Helix Producer I platform and Q4000 rig at the surface, where the oil and gas are separated, stored and some is burned off.