Final Kill? BP Finishes Pumping Cement Into Busted Well

(Aug. 5) -- BP finished pumping cement into its broken oil well today, a crucial step in the process of permanently killing the mile-deep source of the world's largest accidental oil spill.

The British oil giant said it started to inject the cement into the well at 9:15 a.m. CDT as part of its "static kill" operation. About seven hours later, it announced that the process was complete.

The cementing is a major step toward making the ruptured well safe, said retired Coast Guard Adm. Thad Allen, the national incident commander.

"This is not the end, but it will virtually assure us that there will be no chance of oil leaking into the environment," Allen told reporters.

On Wednesday, BP said another part of the static kill -- the pumping of 2,300 barrels of heavy mud down the damaged well shaft over a period of eight hours -- was successful. Pressure from oil trying to gush out of the pipe is being matched by pressure from mud pumped into it, yielding a "static condition" that enabled the injection of cement, BP Senior Vice President Kent Wells told reporters, according to BBC News.

Still, the ultimate solution to make the well safe will be relief wells rather than the static kill. Two relief wells have been drilled down into the same seabed since May and will be used to plug the blown-out well from below.

"We've pretty much made this well not a threat, but we need to finish this from the bottom," Allen told reporters.

The relief well is now 4.5 feet from the blown-out Macondo well, but work on the relief wells has been suspended while cement is being pumped in as part of the static kill. Work will resume once the cement has cured, and the relief wells may be ready this month.

"When the cementing is done, it could take five to seven days to intercept the annulus [the outer casing of the Macondo well] and make a determination of how much mud and cement is needed," Allen said, according to The Times-Picayune.

"I will declare this [well] dead once we've intercepted the annulus," he said.

A rig leased to BP to drill one of the relief wells belongs to the same company that owned the ill-fated Deepwater Horizon rig, and confidential reports obtained by The New York Times show the company, Transocean, had safety concerns about the specific rig that's being used on the relief well. A month before the disaster, Transocean commissioned a safety review of its Houston headquarters and several of its oil rigs because of those concerns. Previous internal Transocean reports obtained by the Times described safety risks on the Deepwater Horizon rig, but the new documents detail concerns about its larger fleet, including the relief well's rig.

The reports are likely to broaden a debate over the cause of the April 20 explosion that killed 11 rig workers and triggered the world's worst accidental oil spill. BP will likely be jostling with Transocean over liability for the disaster, and more evidence about safety concerns pertaining to multiple Transocean rigs could strengthen BP's case.

Amid that investigation, scientists are reviewing results from the static kill procedure, and one of the things they're looking for is any evidence of leaks in the well casing, which could reveal clues about the April 20 explosion.

Nearly 5 million barrels of oil have spewed into the Gulf of Mexico since then, making the Deepwater Horizon disaster the world's largest accidental oil spill. But a new U.S. government report says the vast majority of that oil is believed to have evaporated, been skimmed off the water's surface or dispersed completely -- sparking a debate among gulf residents, scientists and politicians over the spill's real impact.

Some scientists have questioned the report's methodology. "A lot of this is based on modeling and extrapolation and very generous assumptions," Samantha Joye, a marine scientist at the University of Georgia, told The New York Times. "If an academic scientist put something like this out there, it would get torpedoed into a billion pieces."

Other scientists say the report's figures seem plausible. But regardless of whether most of the oil has disappeared, a huge amount still remains.

"When they say that there's 25 percent of the oil remaining, that is almost five times the Exxon Valdez," Ian MacDonald, a professor of oceanography at Florida State University in Tallahassee, told The Washington Post.