Gulf Oil Spill and Deepwater Horizon: "managing expectations" of oil spill volume ... by gimleteye

Photo from the Boston Globe.

The numbers don't add up. What started out as an estimate of 1,000 barrels per day of spilled oil from the Deepwater Horizon disaster quickly changed to 5,000 barrels per day. Based on that revised estimate, I wrote that the current disaster would exceed the Exxon Valdez by mid June.

Independent scientists took it upon themselves and calculated a spill rate much higher: at 26,000 barrels per day. Now comes news that the spill rate could be 70,000 barrels per day, plus or minus twenty percent, based on the BP released video. (click 'read more' for full report) In this case, the disaster already exceeds the Exxon Valdez in volume of oil spilled.

The CEO of BP now admits that his company could have done more to anticipate the response needed for this disaster. Really? BP, TransOcean, and Halliburton are al multi-billion dollar corporations. Do you think that risk analyses hadn't been done to estimate damage from a blowout at the bottom of the ocean? Of course they have and my guess is that these risk assessments were buried to ensure that profits would not be interrupted by outlandish provisions to protect natural resources. Why, even editorial writers like Mike Thomas of the Orlando Sentinel, bought the picture of safe and necessary offshore drilling. These are Thomas' thoughts, published by the Orlando Sentinel on April 23, 2009. Exactly a year after he wrote these words, the Deepwater Horizon rig blew up. "Drilling foes don’t have any recent pictures of oily birds to make their case, so they throw out worst-case scenarios that are about as likely as an oil bit goosing Godzilla out of the depths."

All that oil is just hanging out there in the Gulf of Mexico. Congealing in the water column, drifting, toxic. Where it goes, nobody knows.



(May 13, 2010: Gulf spill could be much worse than believed) The volume of oil pouring into the Gulf of Mexico from the Deepwater Horizon oil rig may be at least 10 times higher than previously estimated, NPR has learned.

The U.S. Coast Guard has estimated that oil was gushing from a broken pipe on the Gulf floor at the rate of 5,000 barrels a day.

But sophisticated scientific analysis of seafloor video made available Wednesday by the oil company BP shows that the true figure is closer to 70,000 barrels a day, NPR's Richard Harris reports.

That means the oil spilling into the Gulf has already far exceeded the equivalent of the 1989 Exxon Valdez tanker accident in Alaska, which spilled at least 250,000 barrels of oil.

The analysis was conducted by Steve Wereley, an associate professor at Purdue University, using a technique called particle image velocimetry. Harris tells Michele Norris that the method is accurate to a degree of plus or minus 20 percent. That means the flow could range between 56,000 barrels a day and 84,000 barrels a day.

Another analysis by Eugene Chiang, a professor of astrophysics at the University of California, Berkeley, calculated the rate of flow to be between 20,000 barrels a day and 100,000 barrels a day.

Even the most conservative of those estimates is much higher than what the Coast Guard has so far said.

But the pipe is spewing both oil and gas and it's not clear in the BP video how much is oil and how much is gas.

BP disputes these results, and maintains there is no reliable way to calculate the flow of oil from a broken pipe.

But, Harris said, the uncertainty could be reduced if BP would share more information with the scientists.