As the Gulf of Mexico entered a third day free of fresh oil from BP’s blown-out well, a company official said Saturday that there were still no signs of damage in the 13,000-foot-deep hole.
“We’re very encouraged at this point,” said Kent Wells, a senior vice president of BP. He said that a test to assess the condition of the well was continuing, and that any decision to end it would be made by Thad W. Allen, the retired Coast Guard admiral who commands the spill response.
“The longer the test goes, the more confidence we have in it,” Mr. Wells said. “But we don’t want to jump ahead of the process we’ve laid out. Admiral Allen is the ultimate decision maker.”
The test began on Thursday afternoon with the closing of valves on a new, tighter-sealing cap atop the well and was expected to last at least 48 hours. With the valves closed, oil stopped gushing into the gulf for the first time since the disaster began with the explosion of the Deepwater Horizon drilling rig on April 20.
The test will help determine whether the well can remain shut off or whether it must be reopened and containment systems restarted.
Two vessels that had been collecting oil through pipes at the well head are on standby, Mr. Wells said, and a third, the Discoverer Enterprise, could be brought in quickly with a device to funnel oil from the top of the cap.
With three containment systems working, Mr. Wells said, “We could very well be collecting all the flow at that point.” The flow rate is estimated at 35,000 to 60,000 barrels of oil per day.
But in reopening the well, engineers would have to let oil gush into the water for a relatively short time to reduce pressure as the containment systems started.
Whatever decisions are made after the test, officials say work on a relief well would continue. It is considered the ultimate solution because it would permanently plug the runaway well.
On Friday, Admiral Allen said that the test results were ambiguous, and that the possibility remained that the well had been breached and that oil and gas were escaping into the surrounding rock and even into the gulf.
But Mr. Wells said on Saturday that there were still no signs of any leakage into the rock formation or up through the seabed into the water. “There’s no evidence that we don’t have integrity,” he said.
He said scientists were “not at all surprised” that pressure readings, while higher than had been forecast if the well was badly damaged, were lower than had been expected if the well was intact. One explanation could be that the reservoir of oil had been depleted by the gushing well, he said.
Mr. Wells said pressure in the well was still slowly rising, which he said was a good sign. Temperature readings showed that the well had cooled off; if oil was still flowing out through a leak, temperatures would be expected to be higher.
Scientists were reviewing data from seismic and sonar surveys as well, which could show if oil was leaking into shallow rock formations. And two remotely operated submersibles had video cameras trained on the seabed.
Video showed occasional small gas bubbles emerging from a valve on the topmost section of casing pipe, which starts at the seabed and is three feet in diameter. Mr. Wells said that instruments would sample the gas as a precaution, but he said that such bubbles were commonly seen coming from subsea wells.