Porous media infiltration is dictated by the interplay between capillary and viscous forces and is, therefore, highly dependent on the flow conditions and the ratio of viscosity to surface tension (capillary number, Ca). The authors used fast confocal microscopy and fluorescent dyes to visualize the dynamics of liquid displacement in wet pores infiltrated by a non-wetting low viscosity liquid. They present a quantitative analysis of the morphology and volume of a trapped wetting phase with different flow conditions (varying Ca values). A SP8 confocal microscope was used to produce high resolution 3D images of the infiltrated pores and measure the volume of the liquid phases.
The results show that, as Ca increases, viscous forces overcome capillary action and the volume of the displaced phase decreases. The trapped phase, moreover, forms pendular structures bridging several pores and its size distribution follows a power law relationship.
This study brings new insights for a better understanding of the dynamics of porous media drainage and how to enhance oil recovery in wet reservoirs. These results should appeal to researchers interested in 3D porous structure visualization, liquid infiltration in porous media, oil recovery, and the environment.
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