气候变化领域集成服务门户

A gas-water equilibrator (GWE) was developed to aid in field research of methane in groundwater and help with predrill and postdrill screening of groundwater wells near natural gas development. Currently, field-based monitoring of methane near natural gas development has been limited to water well headspace measurements, which are not an effective replacement for purging and sampling due to well dynamics. The GWE was designed to operate during well purging and provide real-time field measurements of aqueous methane by equilibrating a continuous stream of gas and groundwater in an equilibrator. Real-time monitoring allows evaluation of trends during water well purging, spatial trends between water wells, and temporal comparisons between sampling events, helps focus an investigation, aids in determining when to collect a representative sample, and provides an immediate assessment of local methane concentrations. The GWE was applied to six groundwater wells at a field site containing natural gas production. Various concentration trends were observed during purging for several wells. Field results from the GWE were also compared to fixed laboratory analysis and indicate good agreement. The GWE can rapidly produce representative aqueous methane concentrations in the field and has an equilibration time of about 10s, which is quicker than other reported equilibrators. This work advances field-based research near natural gas development and provides a new technique for field monitoring of aqueous methane in groundwater.