Impact of the capillary fringe in vertically integrated models for CO2 storage

This paper investigates vertically integrated equilibrium models for CO2 storage. We pay particular attention to the importance of including the effect of fine-scale capillary forces in the integrated equations. This aspect has been neglected in previous work, where the fluids are segregated by a sharp interface. Our results show that the fine-scale capillary forces lead to qualitative and quantitative alterations of the integrated equations. Interestingly, while such forces are dispersive on the fine scale, they lead to self-sharpening of the solution on the integrated scale. We discuss these aspects for injection, leakage, and long-term migration through the application by comparison to common sharp interface models proposed in the literature.