HOUSTON — BP’s volatile oil well in the Gulf of Mexico may finally be locked down and filled with cement within a matter of days. Engineers for the company are preparing to pump heavy drilling mud and then cement into the Macondo well early this week, potentially killing it for good — or at least offering critical clues about any unknown leaks that still have to be plugged.
The effort, known as a static kill, comes just over 100 days after the well blew out, spewing as much as five million barrels of oil into the gulf in the largest oil spill ever in American waters. Attempts to control the well have been marked by repeated failures and disappointments, but officials have become increasingly buoyant in their public comments in the last two weeks, since technicians managed to install a tight-fitting cap that stopped oil from leaking into the gulf.
“We are optimistic that we will get this thing done,” Thad W. Allen, the retired Coast Guard admiral who is leading the federal response to the spill, said last week while discussing the final preparations for the plugging operations.
The static kill, also known as bullheading, is part of a two-pronged strategy to kill the well by cementing it shut twice, once from above with the static kill and then from below, using a relief well.
The approach has been compared by some engineering experts to the folkloric efforts to kill vampires.
“Do I use a wooden stake or a silver bullet? Either will work,” said Donald Van Nieuwenhuise, director of petroleum geoscience programs at the University of Houston, who has followed BP’s efforts to plug the well.
Final victory over the well — which blew out on April 20, crippling the Deepwater Horizon rig and killing 11 drill workers — will not be declared until the completion of the relief well sometime in late August. A second relief well is also being drilled as a precaution, in case the first one fails to complete the job.
In the static kill, technicians working from two ships and a rig platform above the well will pump drilling mud through lines installed earlier this month atop the blowout preventer that failed when the drill rig exploded. The mud, weighing about 13 pounds per gallon, would force oil and gas back into the reservoir. If pressure in the well remains stable, cement will then be poured as a harder sealant.
An earlier effort to pump mud into the well using much of the same equipment, in an operation called a top kill, failed over the Memorial Day weekend because the pressure of the oil and gas pouring out of the well overcame the incoming mud and pushed it back into the gulf waters. But now that the well is capped, and oil and gas are not rushing through the piping, the new effort is thought to have a much better chance at success.
BP plans to begin the static kill either Monday night or Tuesday. It could be completed in as little as a day, or it could take several days. Meanwhile, crews will be completing the final 100 feet of the first relief well. By the end of the week, BP technicians should be able to intersect the crippled well at its bottom and then pump more mud and cement into it for the final kill. That effort and confirmation of success should come by late August, officials estimate.
BP engineers said the static kill and the relief well efforts complement each other, and they expressed confidence that one or both efforts will work. While the static kill may only plug the center well pipe, the relief well will penetrate both the central pipe and the portion of the well between the inner piping and the outer casing. That area — called the annulus, and akin to the space between a straw inserted in a tumbler of water and the glass itself — probably will not be reached by the mud and cement injected by the static kill.
If only the inside casing is leaking, the static kill could finally kill the well. But engineers will be sure that no oil and gas can escape through the annulus only once the relief well is completed and cement is poured through it.
“The well can only be killed from the bottom up,” Admiral Allen told reporters last week.
Still, he added, the static kill is important in large part because it can help determine the stability of the well. If there is a sudden drop in well pressure as mud is pumped into the pipes, that could mean there is a leak somewhere in the well. In that case technicians could seek out the leak with seismic work and other diagnostic testing, and then tackle those leaks with the cement pumped in through the relief well.
For now, the well is capped and experts have concluded that the few seeps and leaks around the well are either irrelevant or come from another oil reservoir altogether. But that does not mean everything is secure.
“No one has come out and said the well has full integrity,” said Greg McCormack, program director of the Petroleum Extension Service at the University of Texas, Austin, suggesting that it was still possible for the well to leak before the relief well was completed. For that reason, he said, the static kill operation makes sense to potentially kill the well two weeks earlier than the relief well would.
“This is just an ultraconservative approach,” Mr. McCormack said, “and at this point in time we should be taking the most conservative approaches. I can’t see any risk.”
BP and government officials are continuing to watch the weather, with an active hurricane season already causing sporadic delays in capping and oil containment work in recent weeks.
“Weather is always our worse nemesis,” Kent Wells, BP’s senior vice president for exploration and production, warned reporters last week. “Storms can pick up and be a factor in the Gulf of Mexico, and we’ll need to adjust our activities and the schedule accordingly.”
Tropical Storm Bonnie delayed work on the static kill and the relief wells for a week, even though it fizzled into a relatively minor storm by the time it reached the well site last weekend.
Poster Comment:
“Do I use a wooden stake or a silver bullet? Either will work,” said Donald Van Nieuwenhuise, director of petroleum geoscience programs at the University of Houston
Either should work on Magic Kenyans.
