MIAMI — The U.S. government said Sunday that a oil seep has been detected in the area of the BP's blown-out oil well at the bottom of the Gulf — a prospect that suggests uncontrolled leaking into the Gulf is possible.
No details were given on the size or exact location of the seep, or to what it was made of — crude oil, methane, natural gases or hydrocarbons. But the prospect is ominous. If oil is entering from areas distant from the well bore, it suggests that areas of the seafloor and substrata are allowing oil to escape.
If this scenario is accurate, the well cap will likely be reopened to prevent the existing environmental disaster from becoming even worse and even harder to fix. Once the valves are open, oil would gush once again into the ocean, cutting the pressure on the well system for the first time in three days.
It is possible, too, that the detection devices have sensed naturally occurring seeps, which are a common phenomenon in the Gulf.
In a letter to BP official Bob Dudley, retired U.S. Coast Guard Adm. Thad Allen said that a seep was in the sea bed, and he directed BP to provide him with information on how to open the choke valve of the oil well as quickly as possible to prevent further damage and seepage.
In his letter, Allen gave BP 24 hours to give him a written update of ‘‘your intentions going forward'' and said that he is "concerned that all potential options to eliminate the discharge of oil be pursued with utmost speed until I can be assured that no additional oil will spill."
He reminded BP that finishing two relief wells should be its priority and told the company to " provide me your latest containment plan" in the case that the current cap's test is suspended.
The letter was released late Sunday. Earlier in the day, BP and federal officials had given differing accounts about the success of the containment cap placed last week on the oil well.
Early Sunday, BP Chief Operating Officer Doug Suttles had indicated that the company wanted to leave it in place until permanent relief wells were finished in August, well beyond the two-to-three day test period BP and the Obama administration had initially announced.
As long as the cap, which was placed Thursday, held, "there is no target set to open the well back up to flow," Suttles had told reporters Sunday. ‘‘No one associated with this whole activity . . . wants to see any more oil flow into the Gulf of Mexico," he said.
But Allen, the U.S. government's point man on the oil spill -- and the person with the final say, outlined a different plan just hours later, saying ‘‘nothing has changed'' and that more testing was needed on the containment cap. "The ongoing well integrity test will continue . . . with the potential for additional extensions in 24-hour increment," he said.
Sunday's letter said the testing would continue but reflected increased government concern about safety issues.
Allen had said more work was needed to better understand why pressure readings from the well cap are lower than expected. There could be two reasons, he said: Either there's less oil in the reservoir because so much has flowed out, or oil is leaking out underground.
A pressure reading of over 7,500 psi, or pounds per square inch, would indicate the well casing is intact. A lower reading could suggest a leak. On Sunday, pressure had reached 6,775 psi, BP said.
“While we are pleased that no oil is currently being released into the Gulf of Mexico and want to take all appropriate action to keep it that way, it is important that all decisions are driven by the science," Allen said in his earlier statement to BP.
Allen previously said that once tests were complete, the cap would be hooked up through nearly a mile of pipes stretching to ships on the surface that will collect the oil. That would mean oil would have to be released back into the Gulf for possibly three days to release pressure from the well.
BP’s Deepwater Horizon drilling rig, exploded on April 20 and sank two days later. Since the well was compromised, some 200 million gallons of crude have fouled the Gulf.