An Experimental Investigation on the Energy Signature Associated With Multiphase Flow in Porous Media Displacement Regimes

Abstract This study investigates the energy signature associated with multiphase flow in porous media displacement regimes. We proposed that net efficiency, as the conversion of external work applied to surface energy generated, provides new insights into the transition of flow regimes. The combined effects of wettability and flow rates on immiscible fluid‐fluid displacement is experimentally investigated using high‐resolution imaging in microfluidic flow cells, which allows for tracking the evolution of interfacial area under applied external work. Our study focuses on the morphology of invasion patterns and the efficiency of conversion of external work to surface energy. The results show that the morphology of invasion patterns under unfavorable displacement condition is sharper than that under favorable displacement condition with larger ratios of length and width for fingers. The efficiency of conversion of external work to surface energy decreases with the increase of contact angles and reduces greatly with the increase of Capillary numbers. With favorable displacement conditions, the efficiency of conversion is consistently higher than that for unfavorable displacement. The trends of external work and surface energy serve as a signature of the transition between different flow regimes, which exhibits alteration especially at low Capillary numbers. The findings highlight the importance of wettability and flow rates in determining the efficiency of fluid‐fluid displacement in porous media. Understanding the energy signature associated with multiphase flow can have implications for various geoscience applications, such as oil/gas recovery, groundwater remediation, and underground energy storage.