Due to recent global climate-change concerns, geologic carbon dioxide sequestration (GCS) has received considerable attention. Two promising GCS injection sites are deep saline reservoirs, and oil reservoirs where CO2 storage and CO2-enhanced oil recovery (CO2-EOR) can occur. While the pure fluid dynamics of the injected CO2 in GCS operations are well understood, we still do not have a full systematic understanding of the potential impact of chemical reactions on the fluid dynamics of both GCS injection site options. In addition, we need effective engineering solutions for potential fractures of seals in GCS. Therefore, this study investigates chemical reactions among, supercritical CO2, brine, organics (from simple carboxylic compounds to complex hydrocarbons), and formation rock under conditions related to these two GCS sites. The broader objectives are (1) to develop engineered solutions for inhibiting fracture propagation and strengthening caprock structures and to predict CO2 transport, and (2) to identify how chemical reactions affect fluid dynamics in CO2-EOR. Our highly interdisciplinary approach will investigate the chemical reactions and dynamics of multiple fluid phases in heterogeneous porous environments. The project will be conducted from the nanoscale to continuum scale. The experimental results will be utilized as input parameters into numerical simulations to predict fluid transport in EOR sites. Our expected results will provide information for designing more efficient and safer geologic CO2 sequestration operations by developing effective engineering solutions to arrest fracture propagation in GCS sites.