Government Announces New, Higher Oil Flow Estimates

BY Lea Winerman  June 10, 2010 at 6:12 PM EDT

Updated 7:05 p.m. ET

The flow of oil into the Gulf of Mexico could have been as low as 20,000 barrels per day and as high as 40,000 or even 50,000 barrels per day before June 3, according to new estimates announced Thursday by U.S.Geological Survey Director Marcia McNutt. The estimates come from a federal panel that includes both government scientists and outside researchers.

We’ve updated our oil ticker to reflect the new minimum.

The numbers presented Thursday are significantly higher than the panel’s last estimate of 12,000 to 19,000 barrels per day, which McNutt announced May 27. And in fact, some members of one working group on the panel had always said that original estimate was too low — they told the NewsHour and other media outlets that that the 12,000 to 19,000 range represented only the lower bound of their original estimate, not the upper bound.

The amount of oil coming out of the pipe right now may be even higher, as the estimates announced Thursday only reflect the flow rate before June 3, when BP sliced off the top of the broken riser pipe in order to fit on a containment cap system. That cut could have significantly increased flow from the pipe. BP has said oil flow may have increased up to 20 percent, and some outside scientists have said that the increase could be even more than that. McNutt said that the panel is now working to estimate the post-slice flow rates.

In a statement to reporters Thursday, McNutt described six different methods that government and outside scientists are using to estimate the flow rate. They include computer analysis of video of the escaping oil plume; analyzing pressure readings from inside and outside the containment cap; using satellite data to estimate the amount of oil floating on the water; modeling geological and other aspects of the oil reservoir; and using an acoustic Doppler technology to measure the rate of flow out of the well.

Three of those working groups had produced new estimates of the oil flow Thursday. The team analyzing video of the escaping oil — the plume team — came up with a best estimate of 25,000 to 35,000 barrels per day, but noted that it could be as low as 20,000 or as high as 40,000 barrels. The team that used satellite data to analyze the oil on the water came up with an estimate of 12,600 to 21,500 barrels per day.

An outside team from Woods Hole Oceanographic Institute, which used the acoustic measurement method, estimated the total amount of material escaping the pipe — including natural gas and debris as well as oil. They came up with an estimate of 0.12 to 0.23 meters cubed per second of material escaping the well. That could equal up to 50,000 barrels of oil per day depending on the ratio of oil to other material, McNutt said, although she added that using the best assumptions of that ratio, it would not be likely to be above 40,000 barrels per day.

McNutt said that the panel was still working to put together each of the working groups’ numbers into another official estimate of the pre-June 3 flow.

“The scientific estimate is still a work in progress,” she said, noting the significant differences between the lowest and highest possible estimates.

And the panel members are now using new data and video from BP to try to estimate the flow from after the riser pipe was cut.

“We have our marching orders on the next order of business,” says Steve Wereley, a member of the plume analysis team. “We have some really nice images [...] And we’re working with those images now to come up with a number that would represent the flow after the riser was cut.”