Oil Containment Cap Tests Delayed

BP was poised Wednesday to carry out a make-or-break test on the integrity of the leaking Gulf of Mexico oil well, following a delay imposed by authorities.

The former Coast Guard chief leading the response to the disaster took the decision to put the test off until Wednesday at the earliest after meeting Energy Secretary Steven Chu, a Nobel-winning physicist, and other experts.

BP is poised to test whether a 82-ton cap can seal the devastating leak without threatening the structural integrity of the well.

But officials fear that if the pressure caused by shutting off the flow of oil increases too quickly, it could send oil shooting up from a new leak on the sea floor -- further aggravating the worst oil spill in U.S. history.

"We continue to prepare and review protocols for the well integrity test -- including the seismic mapping run that was made around the well site," Admiral Thad Allen said in a statement. "As a result of these discussions, we decided that the process may benefit from additional analysis that will be performed tonight and tomorrow."

BP's capping device, which contains three giant valves, was lowered Monday and latched onto the ruptured pipe almost a mile down on the sea floor where only underwater robots can operate.

Once given the go-ahead, BP engineers will gradually close the valves to lock in the oil, in a process expected to last between six and 48 hours.

BP put out a statement shortly after Allen's decision was announced, confirming the test had been put off until more checks could be done.

"This analysis will be conducted tonight and into tomorrow (Tuesday night and Wednesday)," it said. "Consequently, the well integrity test did not start today."

Once the test gets under way, fingers will be crossed in the hope of high pressure readings which would mean there are no other leaks and the valves on the cap can remain closed to effectively seal the well.

Low pressure would indicate oil is seeping out of the external casing of the well, meaning the valves would have to be reopened to reduce the risk of a new gusher on the seabed. Containment operations would then have to resume.

"The worst-case scenario is that it could actually broach back to the sea floor," explained senior BP vice president Kent Wells. "If the tests confirm that we can shut in the well, then the well will obviously be shut in and there will be no leakage into the sea."

Scientists will receive pressure readings every 12 seconds and relay the information to BP and government experts, including Allen and Chu, who was dispatched by President Barack Obama to oversee decision-making for this pivotal moment in the 85-day disaster.

Allen has said that pressure readings anywhere between 8,000 and 9,000 pounds per square inch would indicate that the casing of the wellbore, which extends 2.5 miles below the sea floor, is secure.

That would be good news for the Gulf residents who have seen an estimated 35,000 to 60,000 barrels of oil spewing into the sea daily since an explosion destroyed a BP-leased drilling platform off Louisiana in April.

Tar balls and ribbons of crude have washed up along all five Gulf states, from Texas to Florida, shutting down key fishing grounds and scaring away tourists key to local economic health.

An estimated two million to four million barrels of crude have gushed into the sea since the BP-leased Deepwater Horizon sank on April 22, two days after the blast which killed 11 workers.

BP stressed that it was in uncharted territory on this repair mission.

"The sealing cap system, the Q4000 system, the flexible riser system, and the planned additional containment systems never before have been deployed at these depths or under these conditions, and their efficiency and ability to contain or flare the oil and gas cannot be assured," it warned in a statement.

And whatever happens, BP is continuing to drill two relief wells to intercept and permanently plug the well, with that "kill" operation expected sometime mid-August.