A monitoring system for CO2-EOR and storage based on reactive transport simulation of CO2 migration in groundwater

In CO2-EOR (Enhanced Oil Recovery) and storage projects, there is a high risk of CO2 leakage into groundwater, which will not only affect storage effectiveness, but also cause a variety of environmental consequences. A monitoring system of CO2 leakage is essential to the safety of CO2-EOR and storage projects. Previous monitoring systems have been proposed through theoretical analysis, field test and indoor experiment. In this study, a modeling approach based on simulation of CO2 migration coupled with water-rock interactions in groundwater is proposed to support monitoring system development for CO2-EOR and storage projects. The simulation is undertaken using TOUGHREACT and applied to a case study in the Ordos Basin in China. The case study results indicate that the developed monitoring system has the advantage of offering a precise, timely and comprehensive monitoring scheme based on the dynamics of CO2 leakage and its effects on groundwater composition.