Measurement and analysis of methane emissions from the Canadian oil and gas industry

Abstract

Reducing methane (CH₄) emissions from anthropogenic activities is one of the fastest ways to slow the rate of global warming. The oil and gas (O&G) industry is one of the largest contributors to global CH₄ emissions. Since CH₄ is the main constituent of valuable natural gas, reducing O&G CH₄ emissions has both economic and environmental benefits. On top of that, most of these emissions can be reduced using technologies that exist commercially today. Although the benefits of CH₄ reduction are clear, barriers for acting remain. Despite being a significant source of the global carbon budget, an in-depth understanding of O&G CH₄ emissions are lacking. National CH₄ inventories, which are used to track emissions over time, are also uncertain, partly due to a lack of knowledge and measurements of individual sources. Along with other major O&G producing countries, Canada has committed to significant reductions of CH₄ emissions from the O&G sector. While such commitments are promising, without accurate estimates of the baseline, and an understanding of spatial and temporal patterns, achieving these reductions will be a significant challenge. The overarching goal of this thesis and the individual studies within is to improve current understanding of CH₄ emissions from Canada’s O&G sector, and to ultimately aid in reducing these emissions. This thesis includes a synthesis and analysis of nearly 10,000 site-level CH₄ emission measurements, spanning across geographies that make up most of the country’s onshore O&G production. These data were used to examine CH₄ emission patterns and levels in producing regions that vary in production style, infrastructure, and geography. Production-weighted emission intensities and a total inventory for Alberta were calculated. The measurement-based inventory revealed that CH₄ emissions from the onshore O&G sector are likely underestimated by 50%. Further, a sensitivity analysis of modelled CH₄ emission inventories was performed using available measurement data and infrastructural/production characteristics. The major sources of uncertainty in inventory estimates were assessed using a Monte Carlo analysis. The final component of the thesis is the collection and analysis of the first CH₄ measurements for Canada’s offshore industry, which were collected using an aircraft measurement system. Measurements revealed that unlike the onshore sector, offshore CH₄ emissions are in line with current reported estimates. The primary contributions of this work include the first regionally nuanced estimate of Canadian O&G CH₄ emissions (on and offshore production), including production-weighted emission intensities by development. These new measurement-based estimates fill important knowledge gaps for onshore emission patterns and magnitudes, as well as Canadian offshore CH₄ emissions which have not been previously measured. Additionally, a framework for using sitelevel measurements to estimate CH4 inventories was developed, and the key sources of uncertainty in current official inventories were evaluated. This work also produced a publicly available database of O&G methane emission measurements in Canada, which can be used for future research and policy development. Overall, the outcomes of this thesis will help steer CH₄ reduction efforts across the O&G sector and inform future regulations that are expected as the world collectively moves toward a low-carbon future.