Watchful eye kept on sealed-off Gulf well

WASHINGTON — BP will proceed with its delicate testing of its containment cap that could continue to keep oil from spewing into the Gulf of Mexico from its failed well, but the team monitoring the testing isn't 100 percent confident the cap will be successful.

The team's government and industry experts remain uncertain about whether there's damage to the wellbore somewhere in the 18,000 feet between the ocean floor and the oil and gas reservoir that could mean oil and gas is escaping.

The team fears the new seal could force oil and gas to leak out of weak spots in the well, deep below the floor of the ocean, said retired U.S. Coast Guard Adm. Thad Allen, the national incident commander. So far, the pressure readings haven't caused the team to stop the testing, and nothing in the acoustic and seismic tests indicates a breach.

However, Allen said the team isn't completely sure whether to keep the seal closed or resume collecting oil and gas from the well at the end of the 48-hour testing period.

"It's a very, very good thing that the well is shut in right now, there's no oil being released in the environment," Allen said. "But we're very, very mindful to do no harm, to do nothing that is irreversible in terms of damage to the wellbore."

Late Friday afternoon, the pressure during the test reached only 6,700 pounds per square inch, and it continued to build, at about 2 psi an hour. Engineers wanted to see a reading of at least 6,000 psi but would like to see a reading closer to 8,000 psi.

The team's greatest fear is that the lower pressure readings mean oil and gas is escaping and could cause problems with the relief wells that are only a few feet from the existing well — and are the only sure method of stopping the gush of oil permanently.

So far, extensive testing doesn't indicate any sort of breach in the well, said Kent Wells, a senior vice president at BP.

Some testing will help determine whether the low pressure readings might be caused by situations that don't threaten the well's integrity. They include the possibility that since the well blew out, so much oil and gas has escaped already that pressure in the well has dropped naturally. Wells said the pressure readings they're seeing are close to the models they developed for a depleted reservoir and a well with no breaches.