Most work was halted at the site of BP’s blown oil well in the Gulf of Mexico on Thursday, as a newly formed tropical depression threatened to delay for a week or more the effort to seal off the gusher permanently using a relief well.
BP was awaiting word from the federal leader of the spill response about whether drill rigs, support ships and other vessels would have to evacuate the area, a company spokesman said on Thursday morning.
The relief well has been temporarily plugged because of the weather worries, the company said on Wednesday. With about two days of work still needed to install and cement a last section of steel casing pipe in the relief well, BP did not want to start the casing work and then have to stop it if evacuation was necessary, so it put the work off until the storm passes. Once the casing is in place, a final week’s worth of drilling would be needed to intercept the bad well.
The National Weather Service said on Thursday that the tropical depression, the third so far in what is expected to be a busy hurricane season, had formed in the Bahamas. Its track was expected to run to the northwest into the Gulf of Mexico. It would not reach the Gulf for several days yet, the weather service estimated. But when it does, depending on its path and how much it intensifies, some or all of the ships and rigs at the well site could be forced to leave for safer water.
No decision has been made yet on whether to attempt another well-sealing procedure, called a static kill, in which heavy drilling mud would be pumped into the well in an effort to permanently stop the flow of oil and gas. That procedure, if approved by a government technical team, would only begin after the final casing was installed in the relief well, to reduce the risk of damage to the relief well if something went wrong.
The leader of the response effort, Thad W. Allen, a retired Coast Guard admiral, said if the forecast at the well site was for a severe storm, “we could be looking at 10 to 14 days” when no work could be done on the relief well. Containment projects and other work would have to be suspended as well.Before the tropical depression formed, the relief well was expected to intercept the bad well at the end of July. If the static kill is successful, the only need for the relief well may be to confirm that the well is permanently sealed. If the results from the static kill are ambiguous, though, it would then take at least several days, and perhaps several weeks, to permanently shut the flow from the bad well by pumping mud down the relief well.
Admiral Allen said no decision had been made yet about whether the bad well, which is now capped as part of a test to see whether it can hold pressure, would be left in that condition. After gushing for nearly three months following an explosion and fire that sank a drilling rig, the well has not leaked any oil since last Thursday, when valves on a cap atop it were closed to start the pressure test. If officials decide that it is too risky to leave the well under pressure during a storm, the valves would be reopened and oil would once again spew into the gulf.
Admiral Allen said it was possible that the well would be left shut during a storm but would be closely monitored by remotely operated submersibles for as long as possible. The submersibles, and their relatively fast-moving support ships, would probably be away from the site for only three or four days, he said.
Kent Wells, a BP senior vice president, said on Wednesday that the pressure tests continued to show favorable results. “We have no evidence the well does not have integrity,” he said. “Every day we go longer gives us more confidence.”