Tension high as BP tests new well cap in Gulf of Mexico

FROM WIRE REPORTS The Washington Post, The Associated Press

NEW ORLEANS – BP engineers took the first steps toward choking off the gulf oil well Wednesday night in a white-knuckle "integrity test" that could put a permanent stop to the flow of the gusher – or make the situation worse.

Federal officials greenlighted the test Wednesday afternoon after a 24-hour delay in which government scientists and outside experts demanded more information from BP about possible hazards created by the operation. They are concerned that a spike in pressure as the flow is clamped could blow oil and gas out the casing of the well and into the geological formations.

"What we didn't want to do is compound that problem by making an irreversible mistake," said Thad Allen, the national incident commander.

As of Wednesday, the 85th day of the disaster, between 92 million and 182 million gallons of oil had spewed into the Gulf of Mexico since the Deepwater Horizon rig leased by BP exploded April 20, killing 11 workers.

Late Wednesday afternoon, BP engineers closed the main chimney on the new "capping stack" installed atop the well Monday night. That left oil and gas surging from two other ports, known as the kill line and choke line. The protocol developed by BP and approved by federal authorities called for closing the kill line quickly, then very gradually reducing the flow from the choke line until the well flows no more.

The procedure hit a snag, however, when BP discovered a leak in the choke line. A statement by the company on Wednesday night said the leak "has been isolated and will be repaired prior to starting the test."

No oil and gas is being collected by surface ships, which suspended their containment operations Wednesday afternoon.

Federal officials and BP engineers are anxiously observing what happens to pressures in the well. A steady increase in pressure as the flow is reduced would be a strong sign that the so-called Macondo well, drilled by the now-sunken Deepwater Horizon, is physically intact, and that oil and gas are not leaking into the surrounding mud and rock formations below the gulf floor.

Watching the seafloor

Robotic submersibles are scrutinizing the muddy gulf floor and the base of the blowout preventer for signs of oil or gas rising from below. Scientists are also using seismic and sonar instruments to monitor any possible movement of hydrocarbons in the rock formations surrounding the well.

If the well can handle the high pressures, BP could leave the well shut in, and it would not further pollute the gulf.

If the pressure readings are too low, BP will abandon the test. The well will be reopened and gush anew. BP would then resume trying to capture as much leaking oil as possible, using lines to surface ships and a new "top hat" on the gusher, while continuing to drill a relief well that could kill Macondo with mud and cement.

With the test imminent, BP paused Wednesday in its effort to drill the first relief well, which is only four feet away, laterally, from the Macondo well. The decision to halt work on the relief well was a precautionary move to ensure that hydrocarbons don't surge into the new hole from the Macondo well during the integrity test, BP Senior Vice President Kent Wells said Wednesday. Work on the relief well will resume when the test ends, he said. The drilling of a second relief well had already been suspended, pending results of the first relief well.

Awkward relationship

The final run-up to the integrity test highlighted the awkward relationship between BP and the federal government. The government has authority for all major decisions in the spill response, but BP has the technological expertise for the deep-water engineering. BP had planned to proceed with the test Tuesday, but federal scientists called timeout, asking for more assurances that the oil company had thought through what might go wrong.

The decision to postpone the test for 24 hours was made Tuesday afternoon, but that decision was not announced until Allen and BP put out news releases late Tuesday – continuing a pattern in which officials have waited many hours to inform the public of what is happening in the gulf. In late May, for example, officials waited almost a day to reveal that they had suspended the "top-kill" effort to clog the well with heavy drilling mud.