Journal cover Journal topic
Atmospheric Chemistry and Physics An interactive open-access journal of the European Geosciences Union
doi:10.5194/acp-2017-109
© Author(s) 2017. This work is distributed
under the Creative Commons Attribution 3.0 License.
Research article
07 Apr 2017
Review status
This discussion paper is under review for the journal Atmospheric Chemistry and Physics (ACP).
Mobile measurement of methane emissions from natural gas developments in Northeastern British Columbia, Canada
Emmaline Atherton1, David Risk1, Chelsea Fougere1, Martin Lavoie1, Alex Marshall1, John Werring2, James P. Williams1, and Christina Minions1 1Department of Earth Sciences, St. Francis Xavier University, Antigonish, Nova Scotia, Canada B2G 2W5
2David Suzuki Foundation, Vancouver, British Columbia, Canada V6K 4R8
Abstract. North American leaders recently committed to reducing methane emissions from the oil and gas sector, but information on current emissions from Canadian unconventional developments is lacking. This study examined the incidence of methane in an area of unconventional natural gas development in northwestern Canada. In August to September 2015 we completed almost 8000 km of vehicle-based survey campaigns on public roads dissecting developments that mainly access the Montney formation in northeastern British Columbia. Six survey routes were repeated 3–6 times and brought us past over 1600 unique well pads and facilities developed by more than 50 different operators. To attribute on-road plumes to infrastructural sources we used gas signatures of residual excess concentrations (anomalies above background) less than 500 m downwind from infrastructural sources. All results represent emissions greater than our minimum detection limit of 0.59 g/s at our average detection distance (319 m). Unlike many other developments in the US for which methane measurements have been reported recently, the methane concentrations we measured at surface were close to normal atmospheric levels, except inside natural gas plumes. Roughly 47 % of active wells emitted methane-rich plumes above our minimum detection limit. Abandoned and under-development well sites also emitted methane-rich plumes, but the incidence rate was below that of producing wells. Multiple sites that pre-date the recent unconventional Montney development were found to be emitting, and in general we observed that older infrastructure tended to emit more often (per unit) with comparable severity in terms of measured excess concentrations on-road. We also observed emissions from facilities of various types that were highly repeatable. Emission patterns in this area were best explained by infrastructure age and type. Extrapolating our results across the Montney development, we estimate that the emission sources we located (emitting at a rate > 0.59 g/s) contribute more than 111,800 tonnes of methane annually to the atmosphere. This value exceeds reported bottom-up estimates of 78,000 tonnes for all oil and gas sector sources in British Columbia, of which the Montney represents about 55 % of production. The results also demonstrate that mobile surveys could be used to exhaustively screen developments for super-emitters, because without our intensive 6-fold replication we could have used single-pass sampling to screen 80 % of Montney-related infrastructure. This is the first bottom-up study of fugitive emissions in the Canadian energy sector, and these results can be used to inform policy development in an era of methane emission reduction efforts.

Citation: Atherton, E., Risk, D., Fougere, C., Lavoie, M., Marshall, A., Werring, J., Williams, J. P., and Minions, C.: Mobile measurement of methane emissions from natural gas developments in Northeastern British Columbia, Canada, Atmos. Chem. Phys. Discuss., doi:10.5194/acp-2017-109, in review, 2017.
Emmaline Atherton et al.
Emmaline Atherton et al.
Emmaline Atherton et al.

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Short summary
Methane is a potent greenhouse gas, and leaks from natural gas infrastructure are thought to be a significant emission source. We used a mobile survey method to measure GHGs near Canadian infrastructure. Our results show that ~ 47 % of active infrastructure was emitting. Abandoned wells, which should be plugged, were also associated with emissions. We estimate methane emissions from this development are 111 Mt/year, which is more than previous estimates, but less than similar studies in the US.
Methane is a potent greenhouse gas, and leaks from natural gas infrastructure are thought to be...
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