Business and Community Partners: Report: Low oil spill estimates rested on "unexplained assumptions"

Thursday, October 7, 2010

Report: Low oil spill estimates rested on "unexplained assumptions" - USA Today

Report: Low oil spill estimates rested on "unexplained assumptions"
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A Gulf of Mexico oil spill report says that academic scientists made "greater efforts to be clear and rigorous," than industry and federal scientists, in early leak estimates.
The National Commission on the BP Deepwater Horizon Oil Spill and Offshore Drilling report entitled "The amount and the Fate of the Oil," one of four released Wednesday, details how official leak size estimates went from 1,000 barrels -a-day (bbls/day) to 5,000 bbls/day to the eventual 52,700-62,200 bbls/day starting from the April 20, 2010, Macondo oil well spill that killed 11 workers.
The initial 1,000 bbls/day estimate seems to have, "came from BP without supporting documentation," says the report. While the second 5,000 bbls/day estimate came April 28, from a National Oceanic and Atmospheric (NOAA) scientist inexpert in such analysis, who relied on inaccurate numbers for the size of the leak's oil content and its flow rate (15 centimeters/second or 0.34 miles-per-hour) to make calculations.
Warning the estimate was "inexact", the same unnamed scientist added that the spill might release 10,000 bbls/day, based on surface observations of the leak plume. BP and the federal government stuck to the 5,000 bbls/day estimate of the leak rate until late May.
In contrast, three academic researchers, Timothy Crone of Columbia University, Steven Wereley of Purdue, and Eugene Chiang of the University of California, Berkeley, made much higher estimates after May 12, when BP released images of the leaks to the public, as much as 50,000 bbls/day.
"If the initial estimate was based on bad data, then they did the best that they could," Chiang says, by telephone. "But if they thought the flow rate was 15 centimeters-per-second based on observations, they really made a mistake."
The reports authors say they cannot tell if the low estimates actually slowed the response to the oil spill, but say they likely undermined public confidence in BP and the federal response team, regardless.
A federal flow estimate group finally made an estimate of 52,700-62,200 bbls/day, based on Energy Department readings of flow pressure inside the "capping stack" that finally sealed off the well, and Woods Hole Oceanographic Institute data, says the report. "The emerging consensus is that roughly five million barrels of oil were released by the Macondo well, with roughly 4.2 million barrels pouring into the waters of the Gulf of Mexico."
By Dan Vergano
Tags:
Gulf of Mexico Oil Spill