Fluid-Phase Topology Of Complex Displacements In Porous Media

Chemical compositions determine the properties of fluid-fluid and fluid-mineral interfaces and hence the efficiency of multiphase displacement processes in porous media. These interactions are reflected in the microscopic fluid configuration in the pore space, which may be described by topological means. Fluid-phase topology is a promising and currently emerging field of research; however, it still has only a weak link to multiphase displacement physics. We show how the combination of topological and statistical information can be linked to displacement physics and be used for fingerprinting of displacement efficiency and hence to optimize the chemical injection-water composition. We study displacements of crude oil by alkaline injection water in microfluidics, exemplified by other water-based chemical methods. A complex coupling of fluid flow and fluid-phase behavior has been observed with the formation of emulsion phases during displacements. Oleic phases were analyzed by statistical and topological means, showing a systematic change as a function of alkali concentration linked to emulsification. In particular, Lorenz diagrams and a scaled Euler characteristic have been linked to physical properties and fluid-phase behavior and have been found to be sensitive to changes in injection-water chemistry.