Evolutions in the Elastic Constants of Ca-Montmorillonites with H2O/CO2 Mixture under Supercritical Carbon Dioxide Conditions

Abstract

Clay mineral plays a crucial role in determining permeability and affecting mechanical properties of caprock formations in geologic carbon sequestration (GCS) and enhanced oil recovery (EOR) engineering. In the corresponding environment, CO2–H2O intercalation not only causes swelling or shrinkage of clay mineral but also results in affecting mechanical properties of mineral. However, influence of quantitative CO2/H2O adsorption on mechanical properties of clay still remains unknown. This work investigated evolutions of elastic properties of Ca-MMT with variable CO2–H2O component using molecular dynamic method. Elastic coefficients Cij, bulk modulus K, shear modulus G, Young’s modulus Eii, and Poisson’s ratio Eij were correlated to qualified adsorption of CO2–H2O mixture. We obtained the following conclusions: (1) in-plane elastic constants, bulk modulus, shear modulus, and Young’s modulus E33 had distinct correlation with the profile of d001 spacing as a function of H2O content at fixed CO2 content; (2) n...