BP to try 'top kill' method to plug oil spill

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 yesterday.

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.

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 yesterday, 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 today 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 Barack Obama. And then Obama will fly to the Gulf on Friday for his second visit to the region since the crisis began.

The developments on shore may be overshadowed by what happens in the hours and days ahead in the deep water. 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 such government agencies.

Huge ships and drilling rigs now crowd the surface 5,000 feet above the blown-out well.

Yesterday, the 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.

If all goes as planned, a 30,000-horsepower engine aboard the HOS Centerline vessel 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.

So much of the mud would be forced into the blowout preventer that the well would lose all pressure and would become static. Later, BP would inject cement down the wellbore to permanently seal the well.

The danger is that the top kill could worsen the situation.