(187f) Evolution of CO2 Storage Capacity Associated with Geochemical Reactions in Subsurface

Carbon dioxide (CO₂) can be stored in pore spaces in the subsurface via many trapping mechanisms, including hydrodynamic trapping, residual trapping, solubility trapping, and mineral trapping. Total storage capacity is closely related to storage formation properties, particularly porosity and permeability. In this study, we investigate the evolution of storage capacity during and after CO₂ injection. In particular, we evaluate the variation of porosity and permeability of storage formation caused by geochemical reactions between fluids and rocks. The Morrow B sandstone at the Farnsworth Unit (FWU) enhanced oil recovery with CO₂ (CO₂-EOR) field in northern Texas was selected as a case study. We quantify the impacts of reactive transport on CO₂ storage at FWU by comparing simulation results with or without geochemical reactions. We also evaluate the importance of including the reactive transport component in different CO₂ storage scenarios, i.e., CO₂-EOR and deep saline (assuming zero oil saturation at FWU). We hypothesize that the impact of reactive transport on altering porosity and permeability becomes insignificant when the oil phase presents in the storage scenario.