CO 2 –brine displacement in heterogeneous carbonates
International Journal of Greenhouse Gas Control
The displacement of brine by CO 2 is an important process controlling plume migration and initial porespace utilization in geological CO 2 storage. We present CO 2 -brine unsteady-state core flood experiments to characterize CO 2 -brine primary displacement in Estaillades limestone, a model system for dualporosity carbonates. We analyze the experiments by means of numerical simulations assuming 2-D homogeneous rock and parameterized k r (S W ) relationships. Assisted history matching
... matching methodologies were used to find the k r (S W ) parameters which minimize a mismatch function, giving the best match to the experimental data. We refer the results to the microscopic rock structure and we discuss the limits of applicability. Larger-scale heterogeneity was considered as intrinsic to arrive at a practical and upscaled description of the displacement process. Heterogeneity is discussed by comparing the results to classical relative permeability measurements on samples with a 24× smaller volume, which are less affected by heterogeneity. We found that larger-scale heterogeneity results in lower fluid-phase mobilities.