BP ready to go for 'top kill' to try to plug oil well

Cleanup and containment efforts continue at the Gulf of Mexico site of the oil spill following the Deepwater Horizon explosion.
By Joel Achenbach and Steven Mufson
Wednesday, May 26, 2010

The most critical moment in the oil spill crisis in the Gulf of Mexico is at hand, as BP engineers armed with 50,000 barrels of dense mud and a fleet of robotic submarines are poised to attempt a "top kill" maneuver to plug the gushing well a mile below the surface.

It's far from a sure bet.

"It has been done successfully in the past, but it hasn't been done at this depth," Kent Wells, the oil company's senior vice president of exploration and production, told reporters in a conference call Tuesday.

This will be the first stab at shutting down the well since the April 20 blowout and fire that killed 11 workers on the drilling rig Deepwater Horizon. Efforts to capture the spewing oil have had limited success. The expanding slick has ridden a steady sea breeze onto 70 miles of Louisiana's shoreline and into shellfish-rich estuaries. The sight of oil-soaked brown pelicans is now common. Sticky rust-brown oil slathers the grass in the marshlands. Federal officials closed more fishing grounds Tuesday, bringing the total to more than 54,000 square miles, nearly a quarter of the federal waters in the gulf.

Oil company executives will be grilled in federal hearings resuming Wednesday in a hotel in suburban New Orleans. Later this week, Interior Secretary Ken Salazar is set to deliver a safety review of offshore drilling to President Obama. And then Obama will fly to the gulf on Friday for his second visit to the region since the crisis began. "Like everybody, he's frustrated," Carol Browner, assistant to the president for energy and climate change, told CNN.

The developments on shore may be overshadowed by what happens in the hours and days ahead in the deep water, where the only light comes from the lamps of the robotic submarines. BP's top-kill plan has been devised over more than a month by what BP calls a dream team of engineers from the oil industry and from such government agencies as the Energy Department, the Minerals Management Service and the U.S. Geological Survey. BP has also logged 17,000 suggestions from outsiders, Wells said.

Huge ships and drilling rigs now crowd the surface 5,000 feet above the blown-out well. Two rigs are drilling relief wells but are not expected to complete their work until August. Parked in the middle of everything is the command vessel for the top-kill operation, the 312-foot Helix Q4000. Close by will be the 381-foot HOS Centerline, one of the largest supply ships in the world, capable of pumping 50 barrels of mud a minute. Two other backup ships carrying mud will be nearby.

All the work at depth is performed by the remotely operated vehicles (ROVs), numbering 12 by latest count, and operated from the surface ships while BP engineers monitor the process from Houston. The ROVs have tinkered with the five-story blowout preventer that sits atop the wellhead. They fixed a leaking hydraulic line, for example, using an ordinary wrench pinched by a robotic arm. They also removed the "yellow pod," the brain of the blowout preventer, and engineers repaired it at the surface before replacing it at depth.

On Tuesday, BP engineers began diagnostic tests on the blowout preventer. This is a critical phase in which the company will learn how much pressure must be overcome when the drilling mud is injected into the well. It could also lead them to abort the maneuver.

"We've got a crack team of experts that are going to pore over the diagnostic data," Wells said. "There is a remote possibility that we would get some information that it wouldn't work."

If all goes as planned, a 30,000-horsepower engine aboard the HOS Centerline will pump mud at 40 to 50 barrels a minute to the Q4000 command vessel, then down a newly installed pipe to the gulf bottom, and then through flexible hoses into multiple portals in the blowout preventer.

What happens next would be all-important. The mud would have to go somewhere. The hope is that so much of it would be forced into the preventer that, even as some of it surged up the riser pipe and into the water along with oil and gas, much of it would go to the bottom of the well. The well would lose all pressure and would become static. Later, BP would inject cement down the wellbore to permanently seal the well.

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