When combined, the data tell a story about the fate of the oil and gas in the air, on the surface and in the ocean and enabled a new chemistry-based spill rate estimate of an average of 11,130 tons of gas and oil compounds per day -- close to the official average leak rate estimate of about 11,350 tons of gas and oil per day (equal to about 59,200 barrels of liquid oil per day). In total, approximately 4.2 million barrels of oil were released from the well. Ryerson and his colleagues determined that the visible surface slick represented about 15 percent of the total leaked gas and oil; the airborne plume accounted for about another 7 percent. About 36 percent remained in an underwater plume of droplets about 3,300-4,300 feet below the surface, and 17 percent was recovered directly at the surface through a marine riser. The location of the balance, about 25 percent of the total, is not directly accounted for by the chemical data.
The chemical composition of oil and gas in each of these locations was very different. The underwater plume was enhanced in gases known to dissolve readily in water, the team found. This included essentially all of the lightweight methane (natural gas) and benzene present in the spilling reservoir fluid. The surface oil slick was dominated by the heaviest and stickiest components, which neither dissolved in seawater nor evaporated into the air. And the airborne plume of chemicals contained a wide mixture of intermediate-weight components of the spilled gas and oil.
"The results shed a brighter light on the fate and behavior of the oil," said Reddy, "and may help to prepare for future spills."
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Poster Comment:
60,000 bls/day. Quite some well.