BP stops flood of oil into Gulf of Mexico

With slow, carefully monitored half-turns of a valve 5,000 feet under the sea, BP blocked all of the oil gushing from its Gulf of Mexico well Thursday, but officials warned that pipes below the ocean floor might be too damaged to handle a full seal over the long term.

“As you can imagine, it felt very good not to see any oil going into the Gulf of Mexico,” said BP Senior Vice President Kent Wells, who announced the well closure at a news conference. “What I’m trying to do is maintain my emotions. Remember, this is the start of our test.”

George Barisich, president of the United Commercial Fishermen’s Assn., said the development was the best news southeast Louisiana had heard in 85 days. Still, he wasn’t convinced this was the end.

“We always have to be guarded in a situation like this,” he said. “Just look at what happened with all the other things.”

In Washington, President Obama called the seal from the new, tight-fitting cap, which was affixed to the well Monday, “a positive sign.” But he added, “We’re still in the testing phase.”

The actual test began with the valve’s final turn about 3:35 p.m. Eastern time. With the well fully “shut in,” experts will be able to measure the pressure inside.

If the pressure readings are high — and remain high for 48 hours — it could indicate that the well is intact and no oil is seeping from cracks in its underground pipes.

BP would then move cautiously: After 48 hours, crews would partially open a couple of valves in the cap, allowing a smaller flow of oil to be collected by two containment ships. Meanwhile, the seafloor would undergo seismic testing to ensure that no oil was leaking.

Experts, meanwhile, would evaluate whether it was safe to totally seal the cap again.

But if the pressure is low, it could signal a breach somewhere in the thousands of feet of pipe below the ocean floor. In that case, a full seal might push the oil out of those cracks and into the earth. Oil could eventually make its way to the seabed and create other leaks. BP officials have said that the chance of that happening is remote.

If that scenario does happen, the cap on the well would have to be reopened. Some of the oil could be captured by the containment ships, but much of it could once again belch into the ocean until the end of this month, when BP says it will have the ships and pipes in place to collect the estimated 35,000 to 60,000 barrels of oil escaping each day.

If the latest fix fails, it won’t be the first time hopes have been dashed since the Deepwater Horizon rig exploded April 20, leaving 11 workers dead and setting into motion one of the worst environmental disasters in U.S. history. BP has tried other fixes and failed.

On Thursday, Thad Allen, the former Coast Guard admiral heading the federal response, said that seismic tests conducted before the pressure test showed that “there weren’t any developments on the seafloor or in the formation that will be problematic in proceeding with the well integrity test.”

Allen seemed to be calibrating expectations downward when he declared that sealing the well with the 150,000-pound, custom-built cap had never been the main reason for placing it atop the gusher.

Rather, he said, the cap was to provide two new connections that would allow four ships to collect the oil at once. A full seal, he said, should be considered a “side benefit.” In a statement, he said it “remains likely that we will return to the containment process” of collecting oil in the ships.

Allen and BP officials continued to remind the public that the incident would be over only when relief wells penetrated the well and jammed it permanently with mud and concrete sometime in mid-August.

Louisiana Gov. Bobby Jindal said seal or no, the oil already in the gulf was problem enough.

“We know our battles don’t end even when the well is capped,” Jindal said in a statement. “Millions of gallons of oil are still in the gulf and some estimates show that oil will continue to hit our shores for many more months — or maybe even longer.”

Plaquemines Parish President Billy Nungesser said he knew there was a chance the seal might be not permanent.

Still, hope found a way to bubble to the surface.

“It’s good news,” Nungesser said. “And a possible light at the end of the tunnel.”