Assessment of methane emissions from oil and gas production pads using mobile measurements.
A new mobile methane emissions inspection approach, Other Test Method (OTM) 33A, was used to quantify short-term emission rates from 210 oil and gas production pads during eight two-week field studies in Texas, Colorado, and Wyoming from 2010 to 2013. Emission rates were log-normally distributed with geometric means and 95% confidence intervals (CIs) of 0.33 (0.23, 0.48), 0.14 (0.11, 0.19), and 0.59 (0.47, 0.74) g/s in the Barnett, Denver-Julesburg, and Pinedale basins, respectively. This study focused on sites with emission rates above 0.01 g/s and included short-term (i.e., condensate tank flashing) and maintenance-related emissions. The results fell within the upper ranges of the distributions observed in recent onsite direct measurement studies. Considering data across all basins, a multivariate linear regression was used to assess the relationship of methane emissions to well age, gas production, and hydrocarbon liquids (oil or condensate) production. Methane emissions were positively correlated with gas production, but only approximately 10% of the variation in emission rates was explained by variation in production levels. The weak correlation between emission and production rates may indicate that maintenance-related stochastic variables and design of production and control equipment are factors determining emissions.
Office of Research and Development, U.S. Environmental Protection Agency , 109 T.W. Alexander Drive, Research Triangle Park, North Carolina 27711, United States.
Halley L
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Brantley
Eben D
ED
Thoma
William C
WC
Squier
Birnur B
BB
Guven
David
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Lyon
D000393:Air Pollutants / Q000032:analysis; D001336:Automobiles; D003120:Colorado; D004784:Environmental Monitoring / Q000379:methods*; D004867:Equipment Design; D016014:Linear Models; D008697:Methane / Q000032:analysis*; D008906:Mining / Q000379:methods; D061329:Oil and Gas Fields; D013781:Texas; D014959:Wyoming
D000393:Air Pollutants; D008697:Methane