Hydraulic, Chemical, and Mechanical Response of Sandstone Rocks for CO2 Storage Systems

Abstract Carbon dioxide storage in sandstone formations with desirable permeability represents a viable method for reducing atmospheric CO2 levels and mitigating climate change. In this laboratory study, we investigate the response of a dry Navajo sandstone specimen to constant-rate water injections under vertical loading up to 12 MPa and zero lateral strain conditions. Our measurements and analyses include identifying the heterogeneity features in the internal structure of the rock via X-ray imaging, the geochemical composition of rock minerals via XRD and XRF, the evolution of the axial load and deformations, and fluid pressure upon injection, and the full-field planar deformations on the rock surface through digital image correlation. The initial goal was to understand the fluid flow regimes ranging from diffusive flow to localization of fractures induced by water injection; however, the high permeability of the sandstone would require higher injection rates than the range available in the current pumping system. The results enhance our understanding of fluid flow and damage mechanisms in the near wellbore region, utilizing a multi-phase, multi-scale, and multi-sensor monitoring system to overcome the limitations of traditional single-sensor measurements.