CO2-Brine Displacement in Geological CO2 Sequestration: Microfluidic Flow Model Study

Geological CO2 sequestration is a promising method to reduce atmospheric CO2. Deep saline aquifers are one of the most important sites due to their capacity for CO2 storage. Thus, a better understanding of immiscible brine-CO2 mobility and their saturations including invading patterns in deep saline aquifers as CO2 storage sites is required. Microfluidic model provides the opportunity to discover unrecognized processes and to explore existing theories in fluid flow through porous media. In this study, the microfluidic model is used to explore the effects of both the supercritical carbon dioxide (scCO2) injecting velocity and ionic strength in saline aquifers on scCO2 invading patterns in geological CO2 sequestration. The results show that scCO2-brine displacement ratio increases with (1) increased scCO2 injecting velocity up to 40 μL/min, and (2) decreased ionic strength in the range of 1M~5M NaCl.