An Experimental Study of Multiphase Flow in Deforming Porous Media Subject to Dissolution*

Multi-phase flow in porous media is pervasive in natural and engineering processes such as enhanced oil recovery (EOR) and carbon capture and sequestration (CCS). From a fundamental fluid mechanics perspective, such a flow system has also been an excellent example problem to study instability and percolation theories. To make this problem even more challenging and intriguing, dissolution of the solid matrix can occur in many scenarios, effectively modifying the physical and hydrological properties of the solid structures, which in turn provides a feedback to the flow. However, our fundamental understanding of this coupling effect is still limited. To that end, multiphase flow of aqueous acid and gas is studied using novel calcite-based microfluidic channels. The microfluidic devices used in the experiments were fabricated in calcite using photolithography and wet etching, which offers precise control over their structural and chemical properties and unaberrated optical access to the microscale flow. These experiments provide a unique picture of the flow dynamics in such a complex system as well as develop correlations between pore-scale flow and dissolution rates under various flow conditions.