Investigation of water and polymer flooding for enhanced oil recovery method in differential lobe pore structure

Abstract

ABSTRACT The total recovery of crude oil can be significantly improved by injecting fluids during the secondary and tertiary stages of production. The process leading to improved vertical and areal sweep efficiency is highly influenced by viscous and capillary forces. Along with reservoir rock properties, the reservoir fluid and displacing fluid properties play a critical role during enhanced oil recovery processes. In this study, a two-dimensional differential two-lobe pore throat structure was modelled to investigate the phenomena of water and polymer flooding. Computational fluid dynamics (CFD) with transient analysis was incorporated to study the oil recovery efficiency with changing effect of wettability conditions, and oil and injecting fluid properties. The fractional flow of water at the outlet, breakthrough time, and residual oil saturation were considered as the evaluation factor for numerical experiments. Navier–Stokes equation coupled with the volume of fluid (VoF) model is used to describe the flooding process and for interface tracking. Inconsistent water cut at the outlet was observed in cases with high viscosity contrast. A significant difference in residual oil saturation (10–25%) was observed between water-wet and oil-wet conditions. Polymer flooding improved the total recovery by 7–22% as compared to simple water flooding.