News Release 

Oil and gas well leakage in British Columbia

Proceedings of the National Academy of Sciences

Researchers report a summary of oil and gas well leakage in British Columbia. Leakage from oil and gas wells can lead to groundwater contamination and greenhouse gas emissions. Romain Chesnaux and colleagues analyzed data on wellbore leakage compiled by the British Columbia Oil and Gas Commission to estimate the frequency and pathways of wellbore leakage, as well as the contribution from leakage to greenhouse gas (GHG) emissions. Of more than 20,000 wells in British Columbia tested for leakage, 10.8% had reported leakage during the lifetime of the well. The majority of leakage incidents from active wells involved gas venting from the surface casing, which contributes to GHG emissions, whereas liquid leakage was comparatively rare. Seven abandoned wells reported leakage, in some cases decades after abandonment. Leakage rates were highest for wells drilled after 2010, when regulations requiring testing for leakage after drilling and during routine maintenance went into effect. For wells drilled and/or abandoned before this date, leakage is likely to be underreported, the authors note. The authors estimated that wells with unremediated surface gas leakage produced GHG emissions equivalent to nearly 75,000 metric tonnes of CO2 per year, although the actual value may be higher due to under-reporting of leakage, according to the authors.


Article #18-17929: "A portrait of wellbore leakage in northeastern British Columbia, Canada," by Joshua Wisen et al.

MEDIA CONTACT: Romain Chesnaux, Université du Québec à Chicoutimi, CANADA; tel: 418-545-5011 x5426; e-mail:

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