BP said it has temporarily halted drilling on a nearly complete relief well in the Gulf of Mexico as a precaution while it tests the viability of a new temporary cap.
Kent Wells, a senior vice president with the British energy giant, said at a news conference Wednesday morning that the company would delay drilling on the relief well by as much as 48 hours. The relief well is meant as a conduit to plug the main well with mud and cement, snuffing off the flow of crude once and for all.
Wednesday's announcement came hours after retired U.S. Coast Guard Adm. Thad Allen, the national incident commander for the spill response, issued a short statement around midnight saying it was necessary to suspend the cap test pending further study.
"We want to move forward with this as soon as we are ready to do it," Wells said, adding that it was the government's call late Tuesday to re-evaluate the cap test. He said the test was on hold for at least 24 hours.
In preparation for that test, engineers compiled an extensive seismic survey to determine the state of the undersea rock and spot potential dangers, such as gas pockets, that could threaten the well's integrity under pressure. Allen met with Energy Secretary Steven Chu, the head of the U.S. Geological Survey and BP officials to discuss the seismic data.
"As a result of these discussions, we decided that the process may benefit from additional analysis," Allen said in a statement. He did not elaborate but said work would continue Wednesday.
BP was on the verge of running the test -- intended to see whether the well that extends 13,000 feet below the seafloor is in good enough shape to seal it off -- on Tuesday, a company official told NPR. But scientists decided they wanted more time to study the data and make sure the crucial test gave them the best results for the least risk.
The test involves gradually closing off a series of valves on the temporary cap while carefully monitoring pressure readings in the well to make sure it's safe to continue. There's a slight chance that allowing pressure to build up in the well could increase damage below the seabed and complicate efforts to put a cement plug in the well.
It was unclear whether there was something in the results of the seismic mapping that prompted officials to delay. Earlier, Wells said he hadn't heard what the results were, but he felt "comfortable that they were good."
If the company gets the go-ahead to conduct the test, engineers will be looking for high-pressure readings of 8,000 to 9,000 pounds per square inch. Any result lower than 6,000 might indicate previously unidentified leaks in the well.
If the cap works, it will enable BP to stop the oil from gushing into the sea, either by holding all the oil inside the well or, if the pressure is too great, channeling some of the crude though pipes to collection ships.
BP is ramping up an additional system to collect oil from the blown-out well. A ship called the Helix Producer has been processing some oil and eventually could handle 20,000 to 25,000 barrels a day. A second ship is burning off an additional 8,000 barrels a day.
The cap is only temporary while two relief wells are completed, possibly by late July. The permanent fix would involve infusing heavy drilling mud and cement down one or both of the relief wells to choke off the flow.
Along the Gulf Coast, where the spill has heavily damaged the region's vital tourism and fishing industries, people anxiously awaited the outcome of the painstakingly slow work.
"I don't know what's taking them so long. I just hope they take care of it," said Lanette Eder, a vacationing school nutritionist from Hoschton, Ga., who was walking on the white sand at Pensacola Beach, Fla.
"I can't say that I'm optimistic -- it's been, what, 84 days now? -- but I'm hopeful," said Nancy LaNasa, 56, who runs a yoga center in Pensacola. [Copyright 2010 National Public Radio]