BP Plc stopped the flow from a leaking well in the Gulf of Mexico for the first time in almost three months and said it may know within two days if it is safe to leave the seal in place.
“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 today.
BP’s American depositary receipts gained $2.74, or 7.6 percent, to $38.92 in composite trading on the New York Stock Exchange. One receipt represents six ordinary BP shares.
A test that will measure the pressure inside the well has begun and will last from six hours to 48 hours, BP said in an e- mailed statement today. The test will determine if BP can leave the seal in place or if it will need to let the leak resume until it can be permanently capped with a relief well.
The spill, the biggest U.S. oil spill in history, occurred after 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.
“The sealing-cap system never before has been deployed at these depths or under these conditions, and its efficiency and ability to contain the oil and gas cannot be assured,” the London-based company said.
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 yesterday because a leak developed when it began shutting off the flow to allow pressure to build up.
Shutting in the well using a new cap is an interim step before BP can permanently plug the well with cement, National Incident Commander Thad Allen said in a New Orleans press conference.
“The number one goal is to shut in the well and kill it and stop it at the source,” Allen said today. “This is merely an intermediate step to plugging the hole.”
Engineers today replaced a faulty valve assembly that caused the leak yesterday. BP collected 12,840 barrels of oil yesterday from the well, according to a posting on its website. The company has halted oil collection and drilling of two relief wells that will plug the leak while the pressure test is ongoing.
Low pressure during the first six hours will indicate the well is leaking somewhere else, which would cause BP to stop the test and resume recovering as much oil as possible through lines from the well to vessels on the surface of the Gulf, Allen said.
High pressure readings, between 8,000 and 9,000 pounds per square inch, will show the oil is trapped in the wellbore drilled by the Deepwater Horizon. 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.
Being able to shut in the oil would help in the event a hurricane entered the area before BP permanently plugs the well, Allen said.
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 and Q4000 rig, which are capable of handling as much as 33,000 barrels a day.