Assessing methane emissions from legacy fossil resource development and methane mitigation potential in Atlantic Canada

Lead Proponent

Dalhousie University

Project Background

This project was the first phase of a methane mitigation initiative conducted in the Maritimes, with a focus on legacy (historic) fossil resource (oil, gas, coal) extraction sites. These legacy sites greatly outnumber modern ones in the Maritimes, and were developed generations before modern environmental safeguards.

The objective was to conduct field research and development that results in methane emission inventory estimates for legacy fossil resource extraction sites in Nova Scotia and New Brunswick.

The secondary objective was to provide validation opportunities for new technologies and methodologies that can increase the effectiveness of methane abatement studies everywhere.

Results

The project measured gas migration from legacy fossil fuel sites using a variety of methods, including static chambers, a vehicle-based platform, isotopic analysis of groundwater and drone-based surveying. This generated maps of methane at suspected emission sites, focusing on the Stoney Creek oil and gas field in New Brunswick and several sites in Nova Scotia. In addition to methane emissions data, maps included comprehensive geological structure and stratigraphic characterization of each basin, spectrometry and soil methane sampling, and well water type sections. The project also generated an inventory report and information on soil gas fluxes to provide a baseline for methane emissions from abandoned well and coal sites in Nova Scotia and New Brunswick. These reports can act as a baseline for monitoring environmental performance, and to help develop methane detection strategies within a poorly understood sub-sector of the oil and gas industry.

The project’s policy and economic analysis of mitigation options indicated that methane mitigation cannot be supported solely on economic grounds in the region due to relatively low emissions. An understanding of the costs, benefits, and cost-effectiveness of mitigation will help to inform future policy decisions. Successful identification of gas migration from the abandoned wells and coal sites indicates potential for future work on a larger sample set of legacy sites throughout the Maritimes, with the potential to begin expanding to Western provinces.