Fluctuations in atmospheric pressure can heavily influence how much natural gas leaks from wells below the ground surface at oil and gas sites, according to new University of British Columbia research.
Fluctuations in atmospheric pressure can heavily influence how much natural gas leaks from wells below the ground surface at oil and gas sites, according to new University of British Columbia research. However, current monitoring strategies do not take this phenomenon into account, and therefore may be under- or over-estimating the true magnitude of gas emissions.
The unintentional leakage of natural gas from oil and gas wells into the surrounding subsurface – known as fugitive gas migration – is a major environmental concern that can lead to groundwater contamination and the emission of greenhouse gases into the atmosphere.
“Currently, subsurface gas migration is monitored using infrequent or short-term location-restrictive measurements,” said Olenka Forde, a geological sciences PhD student at UBC and lead author of the study published in Nature Scientific Reports. “Our study shows that the magnitude of gas emissions to the atmosphere can depend on atmospheric pressure before and during the time of monitoring, so short-term, one-time measurements may not be representative of average emissions.”
Variations in atmospheric pressure tend to compress or expand soil gas, with the most significant impact at sites with deep water tables, explains Forde. During a high-pressure system, soil gas is compressed and pushes leaked natural gas deeper underground, where it will likely not be detected at the surface. When atmospheric pressure declines, natural gas trapped below the surface during the previous high-pressure conditions can escape to the atmosphere, contributing to greenhouse gas emissions.
Read more at University of British Columbia
Image: Fluctuations in atmospheric pressure can heavily influence how much natural gas leaks from wells below the ground surface at oil and gas sites, according to new University of British Columbia research. However, current monitoring strategies do not take this phenomenon into account, and therefore may be under- or over-estimating the true magnitude of gas emissions. (Credit: Aaron Cahill)
