BP hopes that the capping stack, pictured above, will successfully stop the 13-week oil leak into the Gulf of Mexico.Photo courtesy of BP America via flickr
NEW ORLEANS, La. — BP was poised Tuesday to test whether a huge cap can hold back crude flooding up from a well below the floor of the Gulf of Mexico, praying an end to the 13-week oil leak may be in sight.
Crucial seismic surveys were being carried out first after underwater robots successfully lowered a 30-foot-tall device known as a capping stack on top of the ruptured wellhead late Monday.
On the 85th day of the worst U.S. oil spill ever, engineers were to start a series of pressure and integrity tests around midday to see if the huge cap, weighing some 75 tons, has indeed choked off the leak.
The tests will last between six and 48 hours, as three different exits from the pipe are slowly closed and careful pressure readings taken.
BP “couldn’t be prouder of the team that put on the sealing cap,” BP senior vice president Kent Wells told reporters. “That went very well and people are feeling really good about that.”
In complex operations being carried out a mile down on the sea floor, BP will now start shutting down the valves on the capping stack, monitoring the pressure as it goes.
A high pressure reading will mean there are no other leaks. But low pressures would indicate that oil was seeping into the Gulf somewhere from the casing of the well deep below the seabed.
“Everybody hope and pray that we are seeing high pressures here,” Wells said. “If the tests confirm that we can shut in the well, then the well will obviously be shut in and there will be no leakage into the sea.”
Coast Guard Admiral Thad Allen, who is in charge of the federal government response to the disaster, said “the biggest unknown” was the condition of the wellbore that extends 2.5 miles below the sea floor.
“It is unknown what happened to that wellbore at the time of the explosion and the events immediately following that,” he told reporters. “I don’t think we’ll know that until we take the pressure readings and see where that information takes us.”
The tests are designed to study whether the capping stack can withstand the pressure on it from the oil still bubbling up from the undersea reservoir.
“In this exercise, high pressure is good,” Allen said. “We have a considerable amount of pressure down on the reservoir. We are looking between 8,000 and 9,000 psi, which would indicate that the hydrocarbons are being forced up and the well can withstand that pressure.”
That would be good news for the Gulf residents who have seen an estimated 35,000 to 60,000 barrels of oil spewing into the sea daily since an April explosion destroyed a BP-leased drilling platform off Louisiana.
In the nation’s worst-ever environmental disaster, tar balls and ribbons of crude have washed up along all five Gulf states, from Texas to Florida, shutting down key fishing grounds and scaring away tourists.
“It is expected, although cannot be assured, that no oil will be released to the ocean for the duration of the test,” BP said Monday, adding, however, that that would not indicate whether the flow had permanently stopped.
The International Energy Agency estimated Tuesday that 2.3 million to 4.5 million barrels of crude have gushed into the sea since the BP-leased Deepwater Horizon sank on April 22.
Despite the endgame under way in the Gulf, there was little optimism at a presidential commission hearing into the causes of the disaster, as victims struggled to come to terms with the damage.
“Even if BP caps this well tomorrow, they’ve done so much damage to the Gulf it’s a strange consolation plan,” said Darwin Bond Graham, a sociologist studying how New Orleans has recovered from Hurricane Katrina.
There was anger too at a new moratorium on deepwater drilling in the Gulf, with Sen. Mary Landrieu (D-La.) saying it could cost some 120,000 jobs.
In recent weeks, much oil has been captured by a containment system and siphoned up to the surface. A new vessel was attached Monday, tripling system capacity.
Officials say that even if the new cap cannot seal the well, the capacity of the system will soon be sufficient to capture all the leaking crude.
BP is also continuing to drill two relief wells to intercept and permanently plug the well. On Tuesday, the first relief well was only 30 feet from the damaged pipe, Wells said.
