Oil leak in choke line delays start of latest test by BP
Thursday, July 15, 2010
A new piece of equipment designed to control the gushing Gulf of Mexico oil well sprung its own leak Wednesday night, the latest setback to BP's efforts to put an end to the environmental disaster.
BP said that the leak in what is known as the choke line could be repaired and that its effort to close the damaged well, and shut down the flow of oil permanently, would resume. But video streams from the seafloor showed a chaotic plume of oil and gas continuing to surge from one of the outlets on the 75-ton cap installed earlier this week.
It was unclear late Wednesday whether the leak would be a momentary hitch in the much-anticipated "integrity test" on the well, or if it would put the operation in grave peril. But the plumbing failure showed once again that nothing has come easy in the long campaign to kill the Macondo well, which blew out April 20 and destroyed the Deepwater Horizon rig, killing 11 workers.
Federal officials green-lighted the test after a 24-hour delay, during which government scientists and outside experts demanded more information from BP about possible hazards posed by stopping the flow of the well. They are concerned that a spike in pressure as the flow is clamped could blow oil and gas out of the casing of the well and into the geological formations. Throughout the crisis, engineers have feared the possibility that efforts to fix the problem could make it worse.
Such concerns ultimately did not dissuade authorities from going forward with what could be a high-reward maneuver. Retired Coast Guard Adm. Thad W. Allen, the national incident commander, said that, notwithstanding the concerns of scientists, he is "gung ho" about the test.
"It will be terrific news if we can shut in the well," Allen said, adding, however, "I don't want to get anyone's hopes up."
Once 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. The protocol developed by BP and approved by federal authorities called for quickly closing one, known as the kill line, then very gradually reducing the flow from the choke line until the well flows no more.
The company said Wednesday night in a statement that the leak in the choke line "has been isolated and will be repaired prior to starting the test."
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 Macondo well, drilled by the now-sunken rig Deepwater Horizon, is physically intact, and that oil and gas are not leaking into the surrounding mud and rock formations below the gulf floor.
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.