Quantifying atmospheric methane emissions from oil and natural gas production in the Bakken shale region of North Dakota

Abstract

We present in situ airborne measurements of methane (CH 4 ) and ethane (C 2 H 6 ) taken aboard a NOAA DHC-6 Twin Otter research aircraft in May 2014 over the Williston Basin in northwestern North Dakota, a region of rapidly growing oil and natural gas production. The Williston Basin is best known for the Bakken shale formation, from which a significant increase in oil and gas extraction has occurred since 2009. We derive a CH 4 emission rate from this region using airborne data by calculating the CH 4 enhancement flux through the planetary boundary layer downwind of the region. We calculate CH 4 emissions of (36 ± 13), (27 ± 13), (27 ± 12), (27 ± 12), and (25 ± 10) × 10 3 kg/h from five transects on 3 days in May 2014 downwind of the Bakken shale region of North Dakota. The average emission, (28 ± 5) × 10 3 kg/h, extrapolates to 0.25 ± 0.05 Tg/yr, which is significantly lower than a previous estimate of CH 4 emissions from northwestern North Dakota and southeastern Saskatchewan using satellite remote sensing data. We attribute the majority of CH 4 emissions in the region to oil and gas operations in the Bakken based on the similarity between atmospheric C 2 H 6 to CH 4 enhancement ratios and the composition of raw natural gas withdrawn from the region.

Mobile measurement of methane emissions from natural gas developments in northeastern British Columbia, Canada

“…This value exceeds the province-wide estimate provided by the government of BC even though the Montney only represents about 55 % of BC's total natural gas production. But, in comparison to studies at select US natural gas sites (Peischl et al, 2016;Karion et al, 2015), our results suggest that natural gas activity in the Montney formation may emit both less frequently and less severely than US comparators.…”

“…Our minimum detection limit of 0.59 g s −1 was used as the emission factor for wells. Facility emission volumes are from Omara et al (2016) amounts of infrastructure allows for a comparison between our CH 4 volume estimate and those of Peischl et al (2016) and Karion et al (2013).…”

“…For example, in May 2014, Peischl et al (2016) conducted airborne surveys of wells that produce more than 97 % of North Dakota Bakken formation oil and gas and found that just under 250 000 t of CH 4 were being emitted annually. According to North Dakota state government records, there were 10 892 producing oil and gas wells in North Dakota at the time of the surveys by Peischl et al (2016). This means that annual CH 4 emissions were an estimated ∼ 23.0 t per well.…”

Atmospheric characterization through fused mobile airborne and surface in situ surveys: methane emissions quantification from a producing oil field

“…Various approaches have been developed to derive surface emissions from CH 4 concentration measurements including direct flux assessment -i.e., measurement of winds and concentrations through a plane -and/or by the comparison of upwind and downwind mass budgets (Peischl et al, , 2016White et al, 1976), data-driven mass balance (e.g., Karion et al, 2013), tracer / tracer ratio (LaFranchi et al, 2013), and assimilation inverse models (e.g., Jeong et al, 2013Jeong et al, , 2012Saunois et al, 2017). Challenges for the last of those approaches include the needs for accurate meteorological transport models and good a priori emission distributions Peischl et al, 2016;Smith et al, 2015).…”

“…Challenges for the last of those approaches include the needs for accurate meteorological transport models and good a priori emission distributions Peischl et al, 2016;Smith et al, 2015). Miller et al (2013) concluded that bottom-up inventories (EPA, 2013;European Commission, 2010) significantly underestimate husbandry and FFI emissions.…”