New field evidence from Canada shows old wells can leave a hidden leakage footprint

Old oil and gas wells may continue to affect the environment long after they have stopped producing, with new field evidence showing that their leakage footprint can be broader and more persistent than surface methane measurements alone reveal. A study led by researchers at The Lyell Centre, Heriot-Watt University, examined persistent methane leakage from a legacy petroleum well in British Columbia, Canada. The team found that while methane emissions at the ground surface were concentrated in a relatively small area and varied through time, the leakage also left a wider detectable signature in the shallow subsurface and surrounding soils.