The only thing keeping millions more gallons of oil out of the Gulf right now is an experimental cap that has held for more than two weeks but was never meant to be permanent.
The so-called "static kill" attempt carries no certainty, and BP PLC engineers still plan to follow it up days later by sending a stream of mud and cement into the bottom of the mile-deep underground reservoir through a relief well they've been digging for months.
But the oil giant's engineers and petroleum experts say it's the clearest path yet to choke the blown-out well and make it even easier for the crews drilling the relief well to ensure oil can never again erupt from the deep-sea well, which has spewed as much as 184 million gallons since the rig connected to it blew up in April and killed 11 workers.
The developments have the makings for an interesting week.
"It could be the beginning of the end," said Darryl Bourgoyne, director of Petroleum Engineering Research Lab at Louisiana State University.
When it begins, crews will slowly pump heavy mud through lines installed last month straight down the throat of the leaky well. If the mud forces the oil back into the massive underground reservoir and scientists are confident the pressure remains stable, then engineers can pump in fresh cement to seal it.
"The only thing that separates the oil from the sea now is the valve. This puts thousands of feet of mud and cement in between," said Eric Smith, associate director of the Tulane Energy Institute. "The idea is to have as many barriers as possible between the ocean and the reservoir. We're adding an extra level of safety."
Officials may then begin the process of choking the underground reservoir feeding the well by pumping mud and then cement down an 18,000-foot relief well. BP officials have long said the process is the only sure way to choke the well for good - plugging up the source of the oil, not just its route to the sea.
No oil has leaked from the busted well since engineers were able to fix a tightly fitting cap over its outlet two weeks ago, and boats skimming the oil and spraying subsea dispersant have been able to contain some of the spill.
BP's engineers, meanwhile, are focused on their latest bid to stymie the oil for good. If the static kill attempt sounds familiar, that's because it is. The company tried a similar process, called a top kill, to choke the well with mud in May. It failed partly because the mud couldn't overcome the flow of the oil.
There's reason to hope this time will be different. For one, the oil is no longer freely flowing from the well, thanks to the temporary cap that has contained the gusher for two weeks. That means that engineers won't have to pump in mud with as much force, said Kent Wells, a BP senior vice president.
There's always the risk that the pressure exerted by the mud will rupture the casing holding in the oil and potentially cause an even greater mess, but experts say it's very unlikely.
"I can't imagine it failing. It's holding pressure and there's no indication of any loss of fluid from the well," Smith said. "It's a vanishingly small risk of failure."
The whole procedure is still set to be completed by late August despite a brief evacuation for Tropical Storm Bonnie last week. And federal officials are downplaying its importance in case of a failure. Allen, the government's point man on the recovery effort, said Sunday that "static kill is not the end all, be all."
Gulf Oil Spill
A crew member looks out at the California Responder oil skimming vessel from the deck of the Pacific Responder in the Gulf of Mexico near the coast of Louisiana Monday, July 12, 2010. The vessels sailed from their home ports in California to the Gulf of Mexico to assist in the containment of oil leaking from the Deepwater Horizon oil well. (AP Photo/Patrick Semansky)
Vessels assisting in the containment of oil from the Deepwater Horizon oil well leak are seen from the Pacific Responder oil skimming vessel in the Gulf of Mexico near the coast of Louisiana Monday, July 12, 2010. (AP Photo/Patrick Semansky)
Crew members connect a hose to an intake for recovered oil while preparing for skimming operations on the Pacific Responder oil skimming vessel in the Gulf of Mexico near the coast of Louisiana Monday, July 12, 2010. The vessel sailed from its home port in the San Francisco Bay Area to the Gulf of Mexico to assist in the containment of oil leaking from the Deepwater Horizon oil well. It arrived near the leak site this morning and is awaiting orders from on-water coordinators. (AP Photo/Patrick Semansky)
The New Jersey Responder oil skimming vessel is seen on the Gulf of Mexico near the coast of Louisiana Monday, July 12, 2010. (AP Photo/Patrick Semansky)
Senior master responder Jeff Bramlett walks past rolled-up oil booms while preparing for oil skimming operations on the deck of the Pacific Responder oil skimming vessel in the Gulf of Mexico near the coast of Louisiana Monday, July 12, 2010. The vessel sailed from its home port in the San Francisco Bay Area to the Gulf of Mexico to assist in the containment of oil leaking from the Deepwater Horizon oil well. It arrived near the leak site this morning and is awaiting orders from on-water coordinators. (AP Photo/Patrick Semansky)
Supervisor Wade Falany handles an oil suction hose while preparing for skimming operations on the deck of the Pacific Responder oil skimming vessel in the Gulf of Mexico near the coast of Louisiana Monday, July 12, 2010. The vessel sailed from its home port in the San Francisco Bay Area to the Gulf of Mexico to assist in the containment of oil leaking from the Deepwater Horizon oil well. It arrived near the leak site this morning and is awaiting orders from on-water coordinators. (AP Photo/Patrick Semansky)
In this image taken from video provided by BP PLC, oil flows from the top of the transition spool at the site of the Deepwater Horizon oil spill in the Gulf of Mexico, Monday, July 12, 2010. Deep-sea robots swarmed around BP's ruptured oil well Monday in a delicately choreographed effort to attach a tighter-fitting cap that could finally stop crude from gushing into the Gulf of Mexico nearly three months into the crisis. (AP Photo/BP PLC) NO SALES
Deck hand Martin Mayorga carries netting while preparing for skimming operations on the deck of the Pacific Responder oil skimming vessel in the Gulf of Mexico near the coast of Louisiana Monday, July 12, 2010. The vessel sailed from its home port in the San Francisco Bay Area to the Gulf of Mexico to assist in the containment of oil leaking from the Deepwater Horizon oil well. It arrived near the leak site this morning and is awaiting orders from on-water coordinators. (AP Photo/Patrick Semansky)
Supervisor Wade Falany handles a rope while preparing for oil skimming operations on the deck of the Pacific Responder oil skimming vessel in the Gulf of Mexico near the coast of Louisiana Monday, July 12, 2010. The vessel sailed from its home port in the San Francisco Bay Area to the Gulf of Mexico to assist in the containment of oil leaking from the Deepwater Horizon oil well. It arrived near the leak site this morning and is awaiting orders from on-water coordinators. (AP Photo/Patrick Semansky)
In this image taken from video provided by BP PLC, the new containment cap, left, is lowered toward the site of the Deepwater Horizon oil spill, right, as a remotely operated vehicle operates in between the two in the Gulf of Mexico, Monday, July 12, 2010. Deep-sea robots swarmed around BP's ruptured oil well Monday in a delicately choreographed effort to attach a tighter-fitting cap that could finally stop crude from gushing into the Gulf of Mexico nearly three months into the crisis. (AP Photo/BP PLC) NO SALES
BP has had more than its share of failures experimenting with other ambitious efforts. So if the oil is already contained and the completion of the relief well appears to be just around the corner, why is the oil giant even bothering to attempt the complicated static kill?
One answer is that it should make it easier to finish the relief well. Crews are also drilling a second, backup relief well a few thousand feet behind the primary one, which is about 100 feet from its target.
If the static kill is successful, though, Smith said they likely wouldn't have to use as much mud to choke the oil. It's also a good way for BP to hedge its bets in case the relief well takes longer than expected to work, he said.
There's a third reason the company has embraced the static kill. Each day the temperature of Gulf of Mexico waters increases, so does the threat of another violent storm disrupting the cleanup process. Federal officials are hoping to end the oil threat once and for all before peak hurricane season, which typically lasts from mid-August to late October.
"If we can get this thing shut in permanently before the August hurricane season, we will have dodged a huge bullet," said Rear Adm. Paul Zukunft, the government's on-scene coordinator.
Contributing to this report were Associated Press writer Harry R. Weber and AP videographer Bonny Ghosh in Venice, La., and AP writer Michael Kunzelman in New Orleans.




