ABOARD THE RESOLUTE, 40 miles off Louisiana — Workers on surface ships continued to flare gas and oil on Tuesday at the site of BP’s runaway well in the Gulf of Mexico, as officials announced that a critical pressure test on the well would be postponed, pending further analysis.
The test would shut the well by closing off valves on a tight-sealing cap that was installed at the wellhead, 5,000 feet down and a few miles from this Coast Guard cutter. But Thad W. Allen, the retired Coast Guard admiral who is overseeing the federal response to the spill, said in a statement on Tuesday evening, “We decided that the process may benefit from additional analysis that will be performed tonight and tomorrow.”
The test, intended to determine whether the well is intact or has been damaged, could be delayed until Wednesday, Admiral Allen said.
On its Web site, BP said in a statement that the test had been postponed after a meeting with Energy Secretary Stephen Chu “and his team of scientific and industry experts.”
BP officials have said that if the test shows that the well can hold pressure, the valve may remain closed. That would end the gusher that began shortly after the Deepwater Horizon drilling rig exploded April 20, killing 11 workers. It would not end the cleanup, however. That could go on for years.
If the test shows the well is damaged, BP officials have said the flow of oil into the sea could still be stopped by increased collection of oil and flaring, a process that could continue for weeks, awaiting completion of a relief well.
“It’s very clear,” Kent Wells, a BP senior vice president, said Tuesday afternoon in describing the pressure test. “What we’re looking for is for pressure to build up. The higher the better.”
Using remotely controlled submersibles, engineers were making last-minute checks in preparation for closing the valves on the cap. For the test they would also shut down the two collection systems, and the flaring would end, at least temporarily.
The test is expected to take as little as 6 hours to 48 hours or more. A short test would mean bad news: the well could not hold pressure, like a leaky soda bottle.
Mr. Wells said scientists from BP and the government would be analyzing the pressure readings throughout the test. “When the data says we need to open up the well, we’ll do that,” he said. “When the data says we can shut it in, we’ll shut it in. We’ll just have to see what the test tells us.”
The installation of the new cap was completed Monday evening, ahead of schedule. “It really went extremely well,” he said. “But we know that the job’s not over yet.”
If containment was still necessary, it would continue until the company could complete the relief well work — by the end of July or August at the earliest.
The flaring came from a drill rig, the Q4000, and from the Helix Producer, which had just started operating Monday. The Helix Producer should be able to collect up to 25,000 barrels of oil a day when it reaches full capacity. Currently, Mr. Wells said, it is at about 12,500 barrels a day. The Q4000 is burning about 8,000 barrels of oil a day.
The test will suspend those operations and also bring to an end a period when more oil had been spewing from the well after a loose-fitting cap was removed to begin work on the new one. The old cap was diverting about 15,000 barrels of oil a day.
If the pressure test shows that the well is damaged and the valves have to be reopened, full containment of the oil would probably not occur for several weeks, until one or two more ships could be brought in to handle more of the flow. That would raise total collection capacity to more than 60,000 barrels a day, the current high-end estimate of the well’s flow rate. Halting the gusher would then await the completion of the first relief well.
The relief well will proceed even if the well is able to remain shut in. When the well intercepts the runaway well, in the next few weeks, heavy mud, followed by cement, will be pumped into the well to seal it permanently.
The well site was an aquatic parking lot on Tuesday, with scores of vessels scattered across the area. The activity was centered on the spot where the Deepwater Horizon burned and then sank two days later.
A huge drill rig, the Development Driller III, was working on the first relief well, now at a depth of close to 18,000 feet. A nearly identical rig, the Development Driller II, was drilling a backup relief well. Supply boats attended both rigs, long sections of casing pipe on their decks.
Ships attended the Helix Producer and the Q4000 as well, spraying seawater to keep the flaring booms as cool as possible.
Ships that service and control the submersibles dotted the area — at last count there were 14 underwater robots at work — and two drilling ships waited nearby.