Fugitive and vented methane emissions surveying on the Weyburn CO2-EOR field in southeastern Saskatchewan, Canada

Abstract

Despite oil and gas related methane (CH4) emissions being the largest anthropogenic source of CH4 in Canada, there are few measurement studies on such emissions to date. That being said, understanding the emissions footprint of different development types is becoming increasingly important in Canada, as the oil and gas sector faces new aggressive regulations to reduce CH4 emissions to 45% below 2014 levels by 2025. In this study, a vehicle-based measurement technique was used to quantify fugitive and vented CH4 emissions from the Weyburn CO2 Enhanced Oil Recovery (EOR) field in southeastern Saskatchewan, Canada. In total, 162 infrastructure sites consisting of 211 active wells and 13 facilities were sampled two or more times. Emission occurrences were substantially low in comparison to other recent emission studies in Canada and the United States, with only 1.85% of sampled sites emitting CH4. We estimated the average emission rate of CH4 at these sites to be ∼0.5 m3/day, which is small compared to the proposed 2020 federal venting cap of ∼110 m3/day. As expected, the low levels of emissions are likely a result of the field's unitized (closed-loop) design, coupled with the operators ongoing commitment to best practice, and the in-depth understanding of the field's characteristics from historical research.