An experimental study of pore-scale flow dynamics and heavy oil recovery using low saline water and chemical flooding

We report a quantitative analysis of pore-scale flow dynamics and displacement behavior of heavy oil recovery at the micro and macro-scale to optimize different chemical flooding processes for enhanced heavy oil recovery. Microscopic studies are performed using micro-particle image velocimetry, which includes low saline water followed by chemical floodings in a 2D porous micromodel to visualize and quantify the displacement process and the oil recovery. The phenomena such as fluctuating flow, flow direction reversal, viscous fingering, film formation around cylinders, unsteady flow behavior, and sudden velocity jumps are observed during low salinity water flooding. Polymer flooding results in no significant change in trapped oil configuration. Alkali-polymer solution injection improves oil recovery as it interacts with crude oil, which results in higher in-situ emulsification, interfacial tension reduction, and change in the contact angle to extremely water-wet conditions. Core flooding experiments are performed to understand the macroscopic behavior and recovery potential of different flooding processes at simultaneous and separate injection modes. The core flooding results showed that the overall heavy oil recovery is 75.37% by simultaneous injection of chemical slugs; however, a separate injection of individual chemical slugs yields lower oil recovery in the case of alkali-surfactant-polymer flooding than the simultaneous injection case. Here, the combined microscopic and macroscopic study provides information about the mechanisms and oil recovery by different chemical flooding processes through the porous medium.