We present a unique microfluidics experimental system that uses geo-material (rock) micromodels and accommodates pressures and temperatures that are encountered in many fossil fuel operations. This system allows us to investigate a wide variety of fluid flow, transport, and chemistry processes that cannot be addressed with experiments at ambient conditions using typical micromodel materials (e.g., glass, silicon). We describe the experimental system in detail, including our versatile micromodel fabrication method that works for a variety of geo- and engineered materials. We present a shale fracture-matrix interaction experiment that shows the importance of imbibition in these systems. Additionally, we present a series of immiscible displacement experiments conducted in shale and glass involving supercritical-CO2 and water. The experiments and discussion highlight the advantages of using rock micromodels for applications involving fossil fuel operations
Micromodels have proven to be effective tools for quantifying flow and transport phenomena in complex porous media [1, 2]. The vast majority of micromodels consist of idealized, thin porous structures etched into engineered materials (e.g., glass, plastic, silicon) in which flow and transport is restricted to two-dimensions . Combined with advanced imaging techniques, microfluidic investigations provide real-time, pore-scale quantification of fluid, interfacial, and mass transfer dynamics - information that is otherwise largely inaccessible in other experimental systems.
Microfluidic flow investigations have the potential to play a large role in future energy resource technologies, especially those related to fossil fuels . Operations associated with fossil fuel production are largely considered reservoir-scale problems, ranging from tens to hundreds of kilometers. However, the fluid flow and transport processes of interest occur within the pores and fractures of rock that are nanometers to millimeters in size, making microfluidics an ideal method for identifying key flow physics that accurately explain reservoir-scale observables.