Informing field-scale CO2storage simulations with sandbox experiments: The effect of small-scale heterogeneities

Abstract

Small-scale heterogeneities can significantly affect the fate of the $C{O}_2$ plume and trapping during CO${}_2$migration. We conducted geologic carbon storage field-scale simulations to investigate the impact of small-scale heterogeneities on plume dynamics and trapping performance. Small-scale heterogeneities have been shown to increase the amount of trapped CO${}_2$during buoyancy-driven flow. The trapped $C{O}_2$ saturation is validated by previous sandbox experimental work during buoyancy-driven flow in realistic heterogeneous domains and is implemented through the critical CO${}_2$saturation parameter (i.e., the first non-zero value in the drainage CO${}_2$relative permeability curve). Depending on the type and degree of heterogeneity, various critical CO${}_2$saturation values are exhibited. Furthermore, we investigated the effect of small-scale heterogeneties when multiple capillary pressure models are employed. This study demonstrates that an increase in critical CO${}_2$saturation reduces the CO${}_2$plume size and lateral extent, accompanying an increase in residual trapping and a decrease in solubility trapping. Finally, we show that independent of the capillary pressure model used, an increase in critical saturation leads to similar CO${}_2$plume dynamics distribution and trapping performance. These results emphasize the importance of quantifying the effect of small-scale heterogeneity as they affect the large-scale behavior of the CO${}_2$plume.