Klotz Louise A, Woolley Liam, Lamarche Bianca, Boutot Jade, Kang Mary
Department of Civil Engineering, McGill University, Montreal, Quebec H3A 0G4, Canada.
Environ Sci Technol. 2025 May 13;59(18):9008-9016. doi: 10.1021/acs.est.4c05602. Epub 2025 Apr 29.
Millions of non-producing oil and gas wells around the world are leaking methane and other contaminants, contributing to increased greenhouse gas emissions and polluting our water, soil, and air. Quantifying methane emissions and understanding the attributes driving these emissions are important for evaluating the scale of the environmental risks and informing mitigation strategies. With our national-scale direct measurement database of 494 non-producing wells across Canada, we find total annual methane emissions from non-producing wells in Canada to be 230 kt/year (51-560 kt/year) for 2023, which is 7 (1.5-16) times higher than estimated in Canada's National Inventory Report (34 kt/year) and accounts for 13% of total fugitive emissions from oil and natural gas systems in Canada. We show that the role of well attributes in methane emissions is best evaluated by considering the emitting component (wellhead/surface casing vent) and the spatial scale (e.g., national, provincial, subprovincial). Large uncertainties in methane emissions from non-producing wells can be reduced not only with additional measurements but also with detailed well attribute analysis using direct measurements. Identifying attributes linked to high emitters can also be used to prioritize mitigation, thereby reducing methane emissions and broader environmental risks.
全球数以百万计的废弃油气井正在泄漏甲烷和其他污染物，导致温室气体排放增加，并污染我们的水、土壤和空气。量化甲烷排放并了解驱动这些排放的属性对于评估环境风险规模和制定缓解策略至关重要。通过我们在加拿大全国范围内对494口废弃油井的直接测量数据库，我们发现2023年加拿大废弃油井的年度甲烷排放总量为230千吨/年（51 - 560千吨/年），这比加拿大国家清单报告中估计的（34千吨/年）高出7倍（1.5 - 16倍），占加拿大石油和天然气系统总逃逸排放的13%。我们表明，通过考虑排放组件（井口/地面套管通风口）和空间尺度（例如，全国、省级、省级以下），能最好地评估油井属性在甲烷排放中的作用。废弃油井甲烷排放的巨大不确定性不仅可以通过额外测量来降低，还可以通过使用直接测量进行详细的油井属性分析来降低。识别与高排放源相关的属性也可用于确定缓解措施的优先级，从而减少甲烷排放和更广泛的环境风险。
