The Permian Basin is located in the southwestern United States, i.e., in parts of Texas and New Mexico. It is the largest oil- and gas-producing region in the U.S, and the oilfield operations there emit the greenhouse gas methane. However, quantifying the methane emissions is difficult because of the large area and the fact that many sources release methane only intermittently. Previous studies have tried to estimate methane leakage in the Permian Basin through satellite images or mobile field studies, but either the resolution was too coarse to quantify methane coming from individual sources, or the studies were limited to small areas or timeframes.

Daniel H. Cusworth, California Institute of Technology, Pasadena, USA, and colleagues have conducted an extensive airborne campaign with imaging spectrometers and identified strong methane point source emissions in the Permian Basin. Airborne imaging spectrometry allows the high-resolution mapping of methane sources across large areas. From September to November 2019, the researchers conducted repeated flyovers using the Next-Generation Airborne Visible/Infrared Imaging Spectrometer (AVIRIS-NG) and the Global Airborne Observatory (GAO) platforms. The team covered about 55,000 km² and 60,000 active wells in the area.

The spectrometers detected 1,100 unique large methane point sources that were sampled at least three times. Most of these sources were highly intermittent (detected 25 % or fewer of the times sampled). Sources that were more persistent emitters (detected 50–100 % of the time) comprised 11 % of the methane emitters but 29 % of the total detected emissions. This could indicate leaking equipment that needs repair. Half of the detected methane came from oil and gas production wells, 38 % from pipelines and other equipment used to collect and transport oil and gas, and 12 % from processing plants. According to the researchers, these results show that frequent, high-resolution monitoring is necessary to understand intermittent methane emitters across large areas and to pinpoint persistent leaks for mitigation.

• Intermittency of Large Methane Emitters in the Permian Basin,
  Daniel H. Cusworth, Riley M. Duren, Andrew K. Thorpe, Winston Olson-Duvall, Joseph Heckler, John W. Chapman, Michael L. Eastwood, Mark C. Helmlinger, Robert O. Green, Gregory P. Asner, Philip E. Dennison, Charles E. Miller,
  Environ. Sci. Technol. Lett. 2021.
  https://doi.org/10.1021/acs.estlett.1c00173