Field investigation of the transport and attenuation of fugitive methane in shallow groundwater around an oil and gas well with gas migration.

'Fugitive' or 'stray' gas migration from deeper formations due to well bore integrity failure has prompted concern regarding environmental impacts. Unintended methane (CH) migration can increase greenhouse gas emissions and affect groundwater quality in the critical zone. Although the CH transport in shallow aquifers has been investigated at experimental injection sites, no intensive groundwater studies have been published around an oil and gas well that has been leaking for a significant period of time.

Free-Phase Gas Detection in Groundwater Wells via Water Pressure and Continuous Field Parameters.

Detection of free-phase gas (FPG) in groundwater wells is critical for accurate assessment of dissolved gas concentrations and the occurrence of FPG in the subsurface, with consequent implications for understanding groundwater contamination and greenhouse gas emissions. However, identifying FPG is challenging during routine groundwater monitoring and there is poor agreement on the best approach to detect the occurrence of FPG in groundwater. In this study, laboratory experiments in a water column were designed to mimic nonflowing and flowing conditions in a groundwater well to evaluate how the presence of FPG affects water pressure and commonly used continuous field parameters.