5 august 2013

Uinta Basin gas leakage far worse than most believe

New study says up to 12 percent of basin’s methane escapes.

By Brian Maffly, The Salt Lake Tribune, Aug 05 2013

Between 6 percent and 12 percent of the Uinta Basin’s natural gas production could be escaping into the atmosphere, far more than commonly estimated, according to a new study led by the National Oceanic and Atmospheric Administration.

These troubling findings emerged during experiments conducted in February 2012 to validate a new method for calculating how much methane is released from oil and gas fields.

"The point of the paper was to show that we have a robust method for verifying emissions," said co-author Colm Sweeney, an atmospheric scientist at the University of Colorado. "The method we’re going after is what is the actual impact to the atmosphere, rather than guesses based on discrete measurements from a few wells."

Accepted for publication in the journal Geophysical Research Letters, the study was conducted by the Cooperative Institute for Research in Environmental Sciences, or CIRES, which Colorado runs jointly with NOAA in Boulder.

The NOAA team piggybacked its work on a study funded in part by Utah examining ozone formation in the basin two winters ago. The team flew over the basin at about 1,000 feet gathering air samples and readings over several weeks.

"We used a mass balance technique, which means we follow an air mass as it moves into the region and then flows out," Sweeney said. "We look at the difference in methane between those two to determine an actual emissions rate for the region."

The study based its findings on measurements recorded during a four-hour window Feb. 3, a calm, cloudless day that was perfect for measuring methane concentrations. There was almost no snow on the ground so the boundary layer over the basin was unusually high for winter, which allowed gas field emissions to mix evenly with the air, Sweeney said.

The basin’s oil and gas infrastructure serves 6,000 wells that account for 1 percent of the nation’s natural gas production.

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