Fugitive Emissions from Conventional and Hydraulically Fractured Natural Gas Developments in Western Canada

Abstract:

Presently, fugitive emissions released into the atmosphere during the completion and production of oil and gas wells are poorly regulated within Canada. Some possible upstream sources of these emissions include flowback during well completions, liquid unloading, chemical injection pumps, and equipment leaks. The environmental benefits of combusting natural gas compared to oil or coal are negated if methane leakages surpass 3.2% of total production, so it is important to have a thorough understanding of these fugitive emissions. This study compares atmospheric leakage pathways of methane and other fugitive gases in both conventional and unconventional oil and gas developments in Western Canada to help fill this knowledge gap.

Over 5000 kilometers of mobile survey campaigns were completed in carefully selected developments in the Montney shale play in British Columbia, and in conventional oil fields in Alberta. These sites are developed by more than 25 different operators. High precision laser and UV fluorescence gas analyzers were used to gather geolocated trace gas concentrations at a frequency of 1 Hz while driving. These data were processed with an adaptive technique to compensate for fluctuations in background concentrations for each gas. The residual excess concentrations were compositionally fingerprinted on the basis of the expected gas ratios for potential emission sites in order to definitively attribute anomalies to infrastructural leak sources. Preliminary results from the mobile surveys of both conventional and unconventional oil and gas sites are presented here. Pathways of methane and other fugitive gases are mapped to their respective sources, identifying common causes of emissions leaks across the oil and gas industry. This is the first bottom-up study of fugitive emissions from Canadian energy developments to produce publicly available data. These findings are significant to operators interested in lowering emissions for economic benefit, as well as public and governmental groups looking to become more informed on the impacts of oil and gas developments in Canada.