A laboratory study of the elastic and anelastic properties of the sandstone flooded with supercritical CO2 at seismic frequencies

Abstract

The paper studies the influence of supercritical CO2 (scCO2) on the elastic and inelastic properties of sandstone at seismic frequencies (0.1 - 100 Hz). The seismic frequency experiments were performed with a low-frequency laboratory apparatus utilizing stress-strain relationship, which was developed to measure the complex Young's moduli of rocks at strain amplitudes from 10-8 to 10-6. The experiments were conducted on water saturated sandstone (Donnybrook, Western Australia) flooded with scCO2. During the experiments with scCO2 the low-frequency system and the pump with scCO2 were held at a temperature of 42° C. The elastic parameters measured for the sandstone with scCO2 at seismic frequencies are close to those obtained for the dry rock. The extensional attenuation was also measured at seismic frequencies for the dry, water saturated and scCO2-injected sandstone. The applicability of Gassmann's theory to saturated scCO2-water mixture was also explored during the experiments.