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UNC researchers say much of oil spill floating under Gulf

Posted May 20, 2010

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— University of North Carolina at Chapel Hill researchers say the amount of oil spewing from a wellhead beneath the Gulf of Mexico is much more than official estimates, and much of the oil is trapped undersea.

Richard McLaughlin, a mathematics professor, said he and his colleagues estimated the British Petroleum well is spilling about 56,000 barrels of oil a day into the sea, which is more than 10 times BP's estimate of 5,000 barrels a day. The UNC estimate is based on the geometry of the broken drilling pipe and the speed of the oil flow seen in underwater video, McLaughlin said.

Simulation shows how oil gets trapped underwater Simulation shows how oil gets trapped underwater

"It’s just a back-of-the-envelope calculation, but I think that we are fairly confident that more is coming out than the 5,000-barrel estimate," he said.

BP's estimate is based on the amount of oil floating on the surface of the Gulf of Mexico, but McLaughlin and mathematics professor Roberto Camassa said much of the oil is trapped far underwater, where it is spreading out in plumes.

The researchers have run simulations in a tank on the Chapel Hill campus that is filled partly with saltwater and partly with freshwater to mimic the denser deep-sea waters and the warmer, lighter water closer to the surface. In their experiments, they spray dyed alcohol, representing the oil, from a nozzle at the bottom of tank and have found that the alcohol spreads out about halfway up the tank and doesn't make it to the top.

The speed at which the oil is gushing from the wellhead is part of the reason its creating underwater plumes, Camassa said.

"(The oil) might not make it all the way to the top, basically, because it encounters some warm layer of water, which is (lighter),” he said. "If you were to release the oil at a much lower speed, it would just make bubbles of oil (that would float to the top)."

McLaughlin said it's difficult to predict what will happen to the "trapped cloud" of oil below the surface.

"There's some uncertainty there, for sure," he said.

John Bane, a professor of marine sciences at UNC, said the movement of deep-sea currents make it hard to say where the oil could end up. Also, the oil is breaking down in the water, he said, with lighter elements eventually floating to the top and evaporating or dispersing and tar-like elements becoming heavier and sinking to the bottom.

Bane said some of the oil could follow the Gulf Stream current and affect the North Carolina coast, but he said the impact would be minimal.

"I don’t think the impact on a North Carolina beach would be some giant pool of black crude oil arriving at the beach," he said, noting it likely would take five to seven weeks for any oil to reach the state.

"That gives the oil a lot of time to disperse and degrade some," he said.

10 Comments

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  • Made In USA May 21, 5:26 p.m.

    Conniebritt, I've read that passage and looked in Revelations for an hour trying to find it. I never did find that exact verse, but all the predictions can be pieced right in with today's happenings. He said he was coming back, and that He could.

  • conniebritt May 21, 3:26 p.m.

    This is horrible.
    From the first time I heard about it My thoughts went to the Bible. The ocean will turn red (be polluted) at the end of time.
    The grasses are already dying in the Gulf.
    These jokers need to go to prison if they concealed tings to save self.

    The Ocean...that's our life blood......Pray and expect a Miracle...That's what is needed....

  • WHEEL May 21, 2:21 p.m.

    Thanks Dr. McLaughlin. When we have a 3 foot deep leak of red alcohol in perfectly calm water I am sure your data will be useful.

  • 5-113 FA Retired May 21, 1:53 p.m.

    Water covers 2/3 of the Earth's surface and is the largest ecosystem. It stands to reason that if the leak goes unchecked, we're screwed.

  • Made In USA May 20, 7:06 p.m.

    This is going to be much larger and MORE damaging that the spill in Alaska.

  • Made In USA May 20, 7:05 p.m.

    What about our good neighbor Cuba...what will they demand of BP and the US if their island bears enviromental harm from this spill?

  • Made In USA May 20, 7:04 p.m.

    This uncontrollable spill will surely harm all forms of life in the oceans at some point and time. I'm now wondering what kind of health affect this will have on humans consuming seafood that has been tainted by the oil. I know on the gas pumps at the gas stations have a sign on them warning that prolonged contact with gasoline may cause cancer.

  • Made In USA May 20, 7:01 p.m.

    Is it possible that this wellhead cannot be fixed and the oil continues to spout out into the Gulf?

  • jackieflash42 May 20, 6:49 p.m.

    Speaking of BP, I couldn't help but notice at the gas pumps that prices have come down just a little bit. However, I also noticed that most of the BP stations haven't. In fact, they seem to be the most expensive in terms of gas prices that stay ahead of the competition by at least 12 cents or more. Hmmmm, guess that extra money they're ripping us off at the pumps is going towards cleaning up the oil spill.

  • tatermommy52 May 20, 6:43 p.m.

    I dont see the govt doing anything or the save the whalers groups protesting.