Impure CO2 Dissolution During Geo-Sequestration in Saline Aquifers with Background Flow

Abstract

Summary In the context of the CO2 sequestration in saline aquifers, purification is costly, then it is required to study the co-injection of impurities to examine its possibility to reduce the project costs. Besides this, some impurities such as SO2 has a hazardous effect on environment. In this process, the dissolution rate of the injected gas into brine is an important factor. After the last two decades, there is an extensive body of published research on the pure CO2. Resulted solution of brine+ dissolved gas for some of these impurities is lighter than brine+ CO2 (like N2), while others produce denser solution (like SO2). To study the dissolution process in the presence of impurities, two samples of these impurities should be considered. Saline aquifers have their own flow (background flow) which can affect the dissolution process. In this study, effect of background flow on the pure CO2 and impure gas stream (97.5% CO2 + 2.5%SO2 and 90% CO2 +10%N2) have been examined. For simplicity in the most studies, effect of heterogeneity wasn’t considered. To verify the results in the more realistic cases than homogeneous systems, simulations were repeated for heterogeneous cases.