Methane gas accounts for approximately 25% of human-caused global warming and is 84 times more effective as a greenhouse gas (GHG) than carbon dioxide, over a period of 20 years. The oil and gas sector produces approximately 44% of Canada’s methane emissions, with methane representing 15% of Canada’s GHG emissions. In light of Canada’s international commitments to combat climate change, regulations have been established to reduce methane emissions from the oil and gas sector by 40-45% from 2012 levels by the year 2025. Ottawa has proposed a regulatory plan regarding equipment leaks, venting, pneumatic devices, compressors and well completions.
GaSP is the first of a multi-phase methane mitigation initiative to be conducted in the Maritimes. This federally funded research and development project (R&D) will focus on legacy (historic) fossil resource (oil, gas, coal) extraction sites.
Why the Maritimes?
In the Maritimes, legacy sites represent the main methane emission threat since most upstream industry (oil and gas) development predates modern regulation. In New Brunswick, 85% if 302 drilled onshore wells sit in a suspended or abandoned state, and 60% of that total were abandoned over 70 years ago. In Nova Scotia, fewer than 1% of the wells drilled are still in production. In both provinces, the majority of wells were decommissioned before proper well abandonment procedures were developed and enforced. The improper sealment of wells can lead to well bore leakage and gas migration, a process which involves uncontrolled migration of thermogenic gas and oil to the surface into shallow groundwater, soil and atmosphere.
The Nova Scotia government has documented approximately 7000 historic coal mine openings, including 1922 pits, shafts, adits and slopes (NSDNR, 2016). Methane liberation declines after mining activity ceases, however abandoned mines can emit methane at a near-steady rate for an extended period of time, and if flooded, only for a few years. Studies of abandoned mines were conducted in the US and, while negligible emissions were detected from several flooded mines, others emitted over 500 000 ft3 of methane per day. Legacy sites in the Maritimes may have been emitting persistently for over a century and could be excellent targets for permanent mitigation.