Abnormal tank emissions in the Permian Basin identified using ethane to methane ratios
Author:
Caulton Dana R.1, Gurav Priya D.1, Robertson Anna M.1, Pozsonyi Kristen1, Murphy Shane M.1, Lyon David R.2
Affiliation:
1. 1Department of Atmospheric Science, University of Wyoming, Laramie, WY, USA 2. 2Environmental Defense Fund, Austin, TX, USA
Abstract
There has been increasing interest in quantifying methane (CH4) emissions from a view toward mitigation. Accordingly, ground-based sampling of oil and gas production sites in the Permian Basin was carried out in January and October 2020. Molar ethane to methane ratios (EMRs) were quantified, which may be used to distinguish emissions from particular sources, such as produced gas and oil tank flashing. The geometric mean EMR for 100 observations was 18 (±2)%, while source specific EMRs showed that sites where emissions were attributed to a tank produced much higher EMRs averaging 47%. Sites with other noticeable sources such as compressors, pneumatics, and separators had lower and less variable EMRs. Tanks displayed distinct behavior with EMRs between 10% and 21% producing CH4 emissions >30× higher than tanks with EMRs >21%. This observation supports the hypothesis that high emission rate tank sources are often caused by separator malfunctions that leak produced gas through liquids storage tanks.
Publisher
University of California Press
Subject
Atmospheric Science,Geology,Geotechnical Engineering and Engineering Geology,Ecology,Environmental Engineering,Oceanography
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