McGill Study Reveals Inactive Oil Wells Emit Microbial Methane at 1,000 Times Expected Rates

Researchers at McGill University discover that non-producing oil wells leak microbial methane at 1,000 times the rate of previous environmental estimates.

By: AXL Media

Published: Apr 10, 2026, 8:11 AM EDT

Source: Information for this report was sourced from EurekAlert!

The Hidden Magnitude of Subsurface Leaks

New environmental research from McGill University has uncovered a dramatic discrepancy in how methane emissions from inactive energy infrastructure are calculated. The study, led by Associate Professor Mary Kang and postdoctoral researcher Gianni Micucci, found that microbial methane is leaking from non-producing wells at rates approximately 1,000 times higher than earlier scientific projections. This discovery suggests that the environmental footprint of abandoned or inactive wells is far more substantial than previously understood, posing a significant challenge for global climate mitigation strategies.

Tracking the Biological Origins of Methane

The researchers distinguished between two primary types of gas: thermogenic methane, which is "cooked" from ancient organic matter deep underground, and microbial methane, which is typically found in shallower formations. While deep petroleum sources were previously considered the primary drivers of leaks, this study identified microbial methane in 23 percent of the sampled wells, a figure three times higher than prior estimates. According to Kang, these non-producing wells can continue to discharge this powerful greenhouse gas even after the original oil or gas targets have been completely exhausted.

Mapping the Scale of Inactive Infrastructure

The geographic focus of the research was Western Canada, home to the vast majority of the country's nearly 500,000 non-producing wells. The team collected and analyzed samples from 401 sites, including inactive wells and those that have never successfully produced. A critical finding from the team's broader research indicates that emissions are highly concentrated, with just 12 percent of the highest emitting wells responsible for 98 percent of the total methane output from this sector. This concentration provides a strategic roadmap for regulators to prioritize specific high impact sites for sealing and remediation.