BP initially estimated that the wellhead was leaking 1,000 barrels (42,000 US gallons; 160,000 litres) a day. On April 28, the National Oceanic and Atmospheric Administration estimated the leak was likely 5,000 barrels (210,000 US gallons; 790,000 litres) a day, five times larger than initially estimated by BP. John Amos, a geologist who has worked as a consultant with oil companies on measuring oil spills, said that figure is the "extremely low end" of their estimates, putting a more realistic figure at 20,000 barrels (840,000 US gallons; 3,200,000 litres) a day. Other sources using satellite imagery have put that number as high as 25,000 barrels (1,100,000 US gallons; 4,000,000 litres) a day. Ian MacDonald, an oceanography specialist at Florida State University, estimated that oil might be leaking at that rate and that the oil slick (as of May 2, 2010) might already contain more than 210,000 barrels (8,800,000 US gal). He later estimated the spill to be about 290,000 barrels (12,000,000 US gallons; 46,000,000 litres). Mike Miller of Safety Boss, a fire-fighting company that specializes in oil wells, suggested that the oil spill may become the biggest in history.
According to BP, estimating the flow is very difficult as there is no metering of the flow underwater. In their permit filed with the Minerals Management Service, BP quotes a worst case daily discharge of 3,900 barrels (160,000 US gallons; 620,000 litres) per day. Before Congress, BP revised their figure upwards to 60,000 barrels (2,500,000 US gallons; 9,500,000 litres) per day if the blowout preventer and other equipment restricting the current flow were removed. Experts contacted by National Public Radio and shown underwater footage of oil and gas gushing out of the broken pipe put the leak rate substantially higher. Steven Wereley, an associate professor at Purdue University used a computer analysis (particle image velocimetry) to arrive at a rate of 70,000 barrels (2,900,000 US gallons; 11,000,000 litres) per day (plus or minus 20%). Timothy Crone, an associate research scientist at the Lamont-Doherty Earth Observatory, used another well-accepted method to calculate fluid flows, estimating the flow is "at least 50,000 barrels a day," and Eugene Chaing, a professor of astrophysics at the University of California, Berkeley, got a similar answer just using pencil and paper, stating "I would peg it at around 20,000 to 100,000 barrels per day," and the earlier figure of 5,000 barrels a day is "almost certainly incorrect."
Interesting article ...Jerry----- Original Message -----From: Gene CramerSent: Monday, May 17, 2010 1:48 PMSubject: [MbrExchange] The Gulf oil spill in perspectiveI thought this was interesting in comparison to what we might say in the nuclear communications business....
The Gulf oil spill in perspective
Orange County REGISTER 2010may16 Letters to the Editor
If the British Petroleum well continues to flow at the rate of 5,000 barrels per day it will exceed the Exxon Valdez spill by the middle of June. But it would take nearly two years to exceed the last big blowout in the Gulf of Mexico. That was Mexico’s (Pemex) Ixtoc I well that spilled nearly 3.5 million barrels over a 10-month period in 1979. Of course, the mother of all spills was in 1991 during the Gulf War in Kuwait where the retreating Iraqi forces set fire to about 700 oil wells that burned off an estimated 800 million barrels of oil before all the wells were capped.
It’s well known, but seldom appreciated by the general public, that, by far, almost all big oil spills come from tanker accidents not offshore drilling. That’s because more than half of the world’s consumption of 85 million barrels of oil per day moves in hundreds of tankers. When they leave and arrive at ports, these tankers are in shallow coastal waters where the danger of collisions and of running aground is severe. Compared to oil well blowouts that are widely dispersed 50 miles offshore, tanker spills can be catastrophic because the entire million-barrel cargo can be released in a few days near the shore.
There have been 13 oil spills world wide that exceeded 700,000 barrels. (So far the BP well has flowed only about 100,000 barrels.) Except for the Kuwait fires and Mexican blowout the other 11 great spills have been from tankers, and the Exxon Valdez was not one of them. That’s a pretty high rate of failure for tankers compared to nearly 8,000 producing offshore oil and gas wells in the Gulf of Mexico.
In the United States we import nearly 12 million barrels of oil a day in a dozen or so tankers. We also deliver another 8 million barrels by pipeline from onshore and offshore production. If the United States continues to prohibit offshore drilling an even larger amount of oil will be delivered by tanker. That may be exchanging a devil we know for a devil we don’t know. We’ll see.
Also, without trying to excuse the events leading up to the blowout, it is instructive to look at our own collective human carelessness. In 2005 there were more than 6.4 million car accidents in the United States that injured 3 million people (one out of every 100 Americans) and killed almost 43,000 of us. Few of these accidents were truly “Acts of God” to use an old euphemism now disdained by trial lawyers. Almost all accidents are caused by poor planning, poor maintenance and/or poor execution. Back to my old refrain, “All accidents are preventable and inexcusable.”
Again, without trying to excuse the BP blowout, we need to be mindful of other catastrophes including two space shuttle explosions out of 131 launches. That’s a pretty high percentage of failure compared to 30,000 oil wells in the Gulf Coast region.
Finally, there is the well-guarded secret that involves all of us. The Environmental Protection Agency estimates that half of the 700 million gallons of motor oil sold in the United States every year is recycled. The other half disappears into the environment. More than 300 million gallons are dumped down the drains or on the ground or drips from our engine crankcases onto highways, parking lots and garages. This oil gets into the ecosystem. Three hundred million gallons a year of lost motor oil equals an Exxon Valdez spill every two weeks!
As we sometimes condemn BP, Exxon and energy companies in general, each of us should be cognizant of our own share of environmental pollution, one drop at a time. Abundant energy is the price we are paying to live in a modern society.
Richard J. Stegemeier, Anaheim
Former chairman and CEO of the oil company Unocal
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