A new look at methane and nonmethane hydrocarbon emissions from oil and natural gas operations in the Colorado Denver‐Julesburg Basin. Issue 11 (3rd June 2014)

• Record Type: Journal Article
• Authors: Pétron, Gabrielle; Karion, Anna; Sweeney, Colm; Miller, Benjamin R.; Montzka, Stephen A.; Frost, Gregory J.; Trainer, Michael; Tans, Pieter; Andrews, Arlyn; Kofler, Jonathan; Helmig, Detlev; Guenther, Douglas; Dlugokencky, Ed; Lang, Patricia; Newberger, Tim; Wolter, Sonja; Hall, Bradley; Novelli, Paul; Brewer, Alan; Conley, Stephen; Hardesty, Mike; Banta, Robert; White, Allen; Noone, David; Wolfe, Dan; Schnell, Russ
• Is Part Of: Journal of geophysical research. Volume 119:Issue 11(2014:Nov.)
• Page Start: 6836
• Page End: 6852
• Publication Date: 2014-06-03
• Subjects: Atmospheric physics -- Periodicals; Geophysics -- Periodicals; 551.5
• DOI: 10.1002/2013JD021272
• Languages: English
• ISSNs: 2169-897X

Abstract

<abstract abstract-type="main"> <title>Abstract</title> <p>Emissions of methane (CH<sub>4</sub>) from oil and natural gas (O&G) operations in the most densely drilled area of the Denver‐Julesburg Basin in Weld County located in northeastern Colorado are estimated for 2 days in May 2012 using aircraft‐based CH<sub>4</sub> observations and planetary boundary layer height and ground‐based wind profile measurements. Total top‐down CH<sub>4</sub> emission estimates are 25.8 ± 8.4 and 26.2 ± 10.7 t CH<sub>4</sub>/h for the 29 and 31 May flights, respectively. Using inventory data, we estimate the total emissions of CH<sub>4</sub> from non‐O&G gas‐related sources at 7.1 ± 1.7 and 6.3 ± 1.0 t CH<sub>4</sub>/h for these 2 days. The difference in emissions is attributed to O&G sources in the study region, and their total emission is on average 19.3 ± 6.9 t/h, close to 3 times higher than an hourly emission estimate based on Environmental Protection Agency's Greenhouse Gas Reporting Program data for 2012. We derive top‐down emissions estimates for propane, <italic>n</italic>‐butane, <italic>i</italic>‐pentane, <italic>n</italic>‐pentane, and benzene from our total top‐down CH<sub>4</sub> emission estimate and the relative hydrocarbon abundances in aircraft‐based discrete air samples. Emissions for these five nonmethane hydrocarbons alone total 25.4 ± 8.2 t/h. Assuming that these emissions are solely originating from O&G‐related activities in the study region, our results show that the state inventory for total volatile organic compounds emitted by O&G activities is at least a factor of 2 too low for May 2012. Our top‐down emission estimate of benzene emissions from O&G operations is 173 ± 64 kg/h, or 7 times larger than in the state inventory.</p> </abstract>