US gives OK for oil well test

2010-07-15 11:00

New Orleans - BP received the green light on Wednesday from the US government to begin a crucial test that could allow the leaking Gulf of Mexico oil well to be sealed once and for all.

After days of painstaking deliberations, Admiral Thad Allen said he gave the British energy giant the go-ahead after overcoming fears the test could lead to "irreversible leakage" below the seabed.

"At this time we will be releasing an order to BP to proceed with the well integrity test," said Allen, the former US Coast Guard chief leading the government's response to the 85-day disaster.

"This test will run for a maximum of 48 hours at which time we will stand down, assess where we're at, and assess the next steps."

Procedures leading up to the actual test, which included disconnecting the Q4000 and Helix Producer vessels which were collecting oil from the wellhead, were already underway.

In addition, "over 40 ocean skimmers and other assets have been positioned around the wellhead" to help contain the additional oil, the joint command centre said, vowing that containment efforts would resume as soon as testing was complete.

Don’t get hopes up

The test involves shutting off the valves on a 75-ton cap installed on Monday to evaluate the integrity of the well bore, which stretches down 4km below the seabed.

High pressure readings would allow the three valves to remain shut and the well would effectively be sealed, but low ones could mean there is a hole somewhere in the casing of the well where oil is escaping.

"It will be terrific news if we can shut in the well but I don't think we can say that," Allen said.

"I don't want to get anybody's hopes up that we can shut this well in until we get the empirical readings we need."

Allen on Tuesday delayed the high-stakes procedure for 24 hours for further analysis to be conducted, and only made the decision to proceed after meetings with top oil industry experts and US officials, including Energy Secretary Steven Chu, a Nobel Prize-winning physicist.

Safety first

The White House said President Barack Obama was being kept up-to-date and sought to reassure the public that the administration was putting safety first.

"Based on new information and analysis, Secretary Chu and other scientists concluded that the test should now proceed with several modifications and safety requirements," the White House said.

"The directive will require additional seismic testing and monitoring from ROV's (Remotely Operated Vehicles) as well as acoustic and temperature monitoring throughout the duration of the well integrity test."

Chu will be involved in the consultations that will take place every six hours during the integrity test, alongside BP and government scientists, on whether to continue the procedure, said BP senior vice-president Kent Wells.

A massive pressure shift could send oil shooting up through a new leak on the sea floor, further aggravating the worst oil spill in US history.

"If the pressure readings stay low, that will tell us that the oil is probably going someplace else and we need to consider the fact we may have a breach in the well bore or in one of the casings," Allen said.

"If that is the case and we have very low pressure readings for about three hours we will probably stop at that point."

A first in 83 days

If the tests are successful, officials say the new cap could give them the ability to capture all the leaking oil in a matter of days.

After months of environmental and economic ruin, the final deliberations were a further agonising delay for anxious Gulf residents whose livelihoods depend on the oil being stopped and the huge surface mess being cleared up.

Once the valves on the cap are closed, no oil will be streaming into the Gulf for the first time since the Deepwater Horizon rig sank 83 days ago.

Drilling on a relief well that is now only 1.2m away from the leaking well will be suspended when the integrity test starts.

Even if the well is found to be secure and the cap is left on, the relief well will be drilled to completion so the oil reservoir can be permanently plugged with cement in a "kill" operation expected in mid-August.

- AFP