COVINGTON, La. —BP is going in for the kill. The trick is to do the job quickly and cleanly.
As early as dawn today, the oil company will try to choke to death the gusher at the bottom of the sea by force-feeding it heavy drilling mud and cement — a tactic called a "top kill" that is routinely used above ground but has never been tried 5,000 feet underwater.
If it's not done just right, it could make the leak worse.
The stakes for BP are high, with politicians and others losing patience with the company over its inability to stop the oil leak that sprang more than a month ago after an offshore drilling rig exploded. Eleven workers were killed, and by the most conservative estimate, 7 million gallons of crude have spilled into the Gulf of Mexico, fouling Louisiana's marshes and coating birds and other wildlife.
"We want what everybody wants — to stop the flow at the source as quickly as possible," said BP spokesman John Curry. "We understand the frustration and we just want to bring this to closure."
Engineers were doing at least 12 hours of diagnostic tests Tuesday. They planned to check five spots on the well's crippled five-story blowout preventer to make sure it could withstand the heavy force of the mud. A weak spot in the device could blow under the pressure, causing a brand-new leak.
A top kill has worked on above-ground oil wells in Kuwait and Iraq. BP CEO Tony Hayward pegged its chances of success in this case at 60 to 70 percent.
Kent Wells, a BP senior vice president, cautioned that engineers are speeding through a planning process that would normally take months. He warned that the top kill could be delayed or scuttled if Tuesday's pressure readings are bad.
If all goes as planned, engineers will pump fluid twice as dense as water from two barges into two 3-inch-wide lines that will feed it into the blowout preventer. Crews plan to pump it in at a rate of 1,680 to 2,100 gallons per minute in hopes of counteracting the upward pressure of the oil gushing to the surface. They stockpiled some 50,000 barrels of the heavy mud, a manufactured substance that resembles clay.
Wells said it could take anywhere from a few hours to two days to determine whether the top kill is working.
If it succeeds, BP plans to follow through by injecting a stream of cement to permanently seal up the well. They may also install a new blowout preventer on top as a fail-safe.