Search

Laboratory experiments and calculation of the dissolution constant were performed to investigate the physical property changes of sandstones in Korea resulting from the geochemical reaction of CO under sequestration conditions. To simulate the sub-surface storage condition (100 bar and 50 °C), the high pressurized stainless cell and chamber were used and the supercritical CO fluid was injected into the cell (or the chamber) by the syringe pump and the pressure regulator. Sandstone slabs and cores were used for the experiments of the supercritical CO-sandstone-groundwater reaction. Results of SEM/EDS and SPM analyses showed that the surface roughness of the slab increased and the precipitation of calcite, halite, and Ca-rich silicate minerals on the sandstone slab occurred during 60 days reaction, suggesting the geochemical weathering process, as a result of CO injection, directly leads to property changes of sandstones in a short time. The average porosity of sandstone cores as increased 8.8% with the corresponding decreases in the dry density, P and S wave velocity, dynamic Young's modulus, and the uniaxial compression strength, indicating that the trend of property changes for the sandstone was well fitted to the first-order reaction curve. The average first-order dissolution constant ( K) of sandstones, calculated by using the loss of sandstone mass during the reaction time was 0.0000846 day. The K values will be useful for estimating the dissolution process of sandstones originated from the supercritical CO-sandstone-groundwater reaction while the CO was injected into the sub-surface. [ABSTRACT FROM AUTHOR]