A New Look at Methane and Non-methane Hydrocarbon Emissions From Oil and Natural Gas Operations in the Colorado Denver-Julesburg Basin

TitleA New Look at Methane and Non-methane Hydrocarbon Emissions From Oil and Natural Gas Operations in the Colorado Denver-Julesburg Basin
Publication TypeJournal Article
Year of Publication2014
AuthorsPétron G, Karion A, Sweeney C, Miller BR, Montzka SA, Frost G, Trainer M, Tans P, Andrews AE, Kofler J, Helmig D, Guenther D, Dlugokencky EJ, Lang PM, Newberger T, Wolter S, Hall B, Novelli P, Brewer A, Conley S, Hardesty M, Banta R, White A, Noone D, Wolfe D, Schnell R
JournalJournal of Geophysical Research: Atmospheres
Date Published2014/05/01/
ISBN Number2169-8996
Call Number256
KeywordsAir quality, Energy, Environment, Hydrocarbons, Industry
Notes

Emissions of methane (CH4) from oil and natural (O&G) gas operations in the most densely drilled area of the Denver-Julesburg (D-J) Basin in Weld County located in northeastern Colorado are estimated for two days in May 2012 using aircraft-based CH4 observations and planetary boundary layer height and ground-based wind profile measurements. Total top-down CH4 emission estimates are 25.8 ± 8.4 and 26.2 ± 10.7 tonnes CH4/hr for the May 29 and May 31 flights, respectively. Using inventory data, we estimate the total emissions of CH4 from non-O&G gas related sources at 7.1 ± 1.7 and 6.3 ± 1.0 tonnes CH4/hr for these two 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 tonnes/hr, close to three times higher than an hourly emission estimate based on EPA's Greenhouse Gas Reporting Program data for 2012. We derive top-down emissions estimates for propane, n-butane, i-pentane, n-pentane, and benzene from our total top-down CH4 emission estimate and the relative hydrocarbon abundances in aircraft-based discrete air samples. Emissions for these five non-methane hydrocarbons alone total 25.4 ± 8.2 tonnes/hr. Assuming these emissions are solely originating from O&G related activities in the study region, our results show that the state inventory for total VOC emitted by O&G activities is at least a factor of two too low for May 2012. Our top-down emission estimate of benzene emissions from O&G operations is 173 ± 64 kg/hr, or seven times larger than in the state inventory.

URLhttp://onlinelibrary.wiley.com/doi/10.1002/2013JD021272/abstract
Short TitleJ. Geophys. Res. Atmos.