ATLANTA — After 72 hours of testing, a BP executive said Sunday that the seal atop its troubled oil well could remain in place until the well is permanently plugged.
But federal officials, worried that the seal could cause more harm than good, left open the possibility of uncorking the well and letting the oil flow into the Gulf of Mexico again, at least temporarily.
The well was fully sealed Thursday for the first time in 85 days using a massive, custom-built cap. Since then, both BP and government officials have acknowledged that the seal plan may prove too risky and have to be abandoned.
But while BP officials have been cautiously optimistic about the seal, federal officials have seemed considerably more worried.
In a Sunday morning press conference, BP chief operating officer Doug Suttles said pressure readings from tests inside the well did not seem to indicate that the well was cracked. A cracked well would mean trouble, because the cap could exacerbate the flow and create new oil leaks on the ocean floor.
"We're not seeing any problems, at this point, of any issues with the shut in," Suttles said. He added that if "encouraging signs continue," the company hoped to keep the well sealed at the top until a relief well could permanently plug it with mud and concrete — a goal that may not be achieved until mid-August.
But an Associated Press report Sunday, citing an unidentified federal official, said scientists were worried about a "seep and possible methane" close to BP's well head off the Louisiana coast. The report did not identify what substance was seeping.
BP spokesman Mark Salt declined to comment on the report, except to say the company "continues to work with the government and share data."
Thad Allen, the federal oil spill response chief, released a statement Sunday that did not mention any known problems on the sea floor. Rather, he said, the government may extend the well test — and, by extension, the seal of the well — in 24-hour increments. The testing had been set to expire Sunday afternoon.
As a condition of the extensions, Allen said, the government would require "significant new monitoring and periodic evaluation and approval" by a federal science team.
He also said more work needed to be done to understand "lower than expected" pressure readings inside the well. Suttles said the pressure was at 6,778 pounds per square inch Sunday. The company has said the well was most likely to be in good shape if the readings were 7,500 psi or above.
BP officials suspect the low readings are not due to a leaking well, but to a loss of pressure from the reservoir, because so much oil has escaped.