Non-Producing Wells Emit Methane 1,000x Higher
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- McGill University researchers found microbial methane leaking from non-producing oil and gas wells at rates about 1,000 times higher than previously estimated, according to a study published in Environmental Science and Technology.
- The study detected microbial methane in 23% of non-producing wells sampled — roughly three times higher than earlier estimates — with traces found in another 50% of wells.
- Canada has nearly 500,000 non-producing oil and gas wells, and the team sampled 401 across the country, particularly in Western Canada, where more than 90% of such wells are located.
- Mary Kang, Associate Professor of Civil Engineering and study co-author, said non-producing wells "could continue to emit microbial methane long after the targeted formation has been fully depleted."
- The researchers noted that most methane leaks typically derive from "thermogenic" sources deep underground, but the contribution of microbial methane, found in shallow formations, has been significantly underestimated.
- Previous research by the same team found the top 12% of emitting wells account for 98% of emissions from this source, suggesting a small number of sites drives the vast majority of leaks.
Why it matters: With nearly 500,000 non-producing wells in Canada alone, the finding that microbial methane emissions are 1,000 times higher than estimated could materially reshape national emissions inventories and regulatory priorities. The researchers' prior finding that 12% of emitting wells account for 98% of emissions suggests targeted monitoring of a small subset of sites could capture most leaks.
