What if BP Never Stopped the Oil in the Gulf of Mexico? Engineers say blown-out well could leak for years if not stopped.

June 4, 2010  -- BP said today that its latest try to control the oil spilling into the Gulf of Mexico may be working. It has lowered a large cap over the blown-out well, 5,000 feet below the surface of the Gulf, in hopes of siphoning off the escaping oil.

"I am actually pretty confident this is going to work," BP COO Doug Suttles said on "Good Morning America." "It probably won't capture all of the flow but it should capture the vast majority."

But this is the seventh attempt to stop the well since the Deepwater Horizon drilling rig exploded and burned on April 20, six weeks ago, and all the others have ended in disappointment.

Which raised a question: What if nothing worked at all? What if the oil just kept coming out of the ground until it stopped naturally? How long would it take? What would be the consequences?

The quick answer is that they would be severe -- though nobody is quite sure how much oil might escape because nobody, even at BP, is sure how much is down there.

"It's huge. It's a big oil field," said Roger Anderson, an oil geophysicist at the Earth Institute of Columbia University. "If 20,000 barrels a day are escaping, it could stay there for years, then drop off. It could flow at a small rate for a very, very long time."

Calls to more than a dozen experts yielded similar answers: it might be years, not months, if nothing stops the gusher, but it would not stretch into a decade. Many engineers and agencies said they would prefer not to guess.

The theoretical question -- what if the oil were allowed to stop on its own -- is not something that the federal government, states along the Gulf Coast, or BP would even consider. The eyes of the world are on the ongoing disaster, and BP is drilling relief wells to divert the leaking oil if nothing else works. The company has said it should be done by August. The government said Thursday that 30,000 people are involved in the effort to control the oil and clean up the mess.

"People are pretty confident that the relief well(s) will work, if nothing else," said Eric Adams of the Massachusetts Institute of Technology in an e-mail to ABC News. "Of course they won't be finished until August, which is 2-plus months away. At 12,000 to 19,000 barrels of oil per day, that is, of course, a lot of oil."

Vast Underwater Oil Field

The Deepwater Horizon was drilling a so-called exploratory well when the accident happened. Eleven workers on the platform never were seen again and are believed to have died. The underground formation that the rig was probing has been estimated to hold anywhere from 50 million to a billion barrels of oil that could be extracted economically.

"Not all the oil would flow out due to what the oil field types would call 'natural bridging' of the well -- that means self-plugging," said Ian MacDonald, an oceanographer at Florida State University who has been studying the size of the spill. "Nonetheless, there is no immediate prospect of 'running out' of oil and gas that can get out if they can't plug this damned thing."

What if BP Never Stopped the Oil?

Where would the oil go? Computer models developed by the federally-funded National Center for Atmospheric Research showed that if parts of the floating slick spread into the powerful Loop Current near Florida's Gulf Coast, oil could be drawn around the Florida peninsula, up the Eastern Seaboard and out into the Atlantic Ocean.

Some oil naturally would be consumed by microorganisms or degraded by sunlight and wave action, but oil might also wash ashore from Louisiana to Florida and up to the Carolinas.

Past experience in the Gulf of Mexico has been sobering. In 1979, a Mexican-owned rig called Ixtoc-1 suffered a blowout and collapsed, and 140 million gallons of oil escaped into the water. Pemex, the Mexican oil company, drilled two relief wells -- and even then oil kept escaping for three months after the first one was finished.

Engineers say major oil accidents are relatively rare, considering the amount of crude that is pumped out of the ground around the world. But the technology to bring a blown well under control has not greatly advanced since the Ixtoc accident, which remains the world's largest.

President Obama, on his third visit to Louisiana since the BP accident, said today, "It is way too early to be optimistic."