Transport dynamics of droplets encapsulated by an elastic interface in pore throats

Abstract

The transport dynamics of droplets in pore throats are crucial for oil recovery in high water-cut oil fields and primarily governed by interfacial properties of droplets. In nanoparticle flooding, nanoparticle surfactants adsorb onto the oil droplet interface, forming a “solid-like” interface that predominantly exhibits elastic properties. Owing to the demonstrated effect of the elastic interface on droplet deformation, new behaviors of droplets encapsulated by an elastic interface would exist when transported through pore throats. In this paper, an elastic interface model was developed and fluid–structure coupling was used to simulate the transport dynamics of elastic interface droplets under the variation of capillary numbers, viscosity ratios, and pore throat structures. The findings showed that: (1) In symmetric pore throats, elastic interface droplets require a higher critical capillary number to pass through compared to clean droplets. The elastic interface restricts the deformation and velocity of droplets when passing through the pore throats. (2) In asymmetric pore throats, the deformation and pass through of elastic interface droplets are inhibited with increasing asymmetry. The restriction effect of elastic interface on droplets transport in the pore throats is consistent at various asymmetries. These results enhance the understanding of droplet transport dynamics in pore throats and provide new insights for improving nanoparticle-enhanced oil recovery technology.