Comprehensive numerical study of sequential injection of SiO2-nanofluids for enhanced oil recovery

Abstract

Improving the efficiency of oil production is an important element in reducing the carbon footprint of the oil industry. One of the methods for increasing the efficiency of oil recovery is the use of oil flooding using solutions of various chemical reagents. The paper presents a computational investigation of the oil recovery from a porous micromodel using a nanofluid during sequential injection of water-SiO2 nanofluid-water. The effect of the nanosuspension concentration, duration of injection of the nanosuspension, the starting time point of nanosuspension injection, as well as the influence of oil viscosity on the oil recovery during sequential injection of main displacement fluid and nanosuspensions was investigated. Such a systematic study was performed for the first time. It was found that injection of three pore volumes of nanosuspension increases oil recovery factor by 1.5 times compared to injection of three pore volumes of water. It has been established that, from a practical point of view, it is most effective to increase oil recovery by starting the injection of nanosuspension after injecting two pore volumes of water. This case leads to an increase in recovery factor by 1.35 times compared to the injection of three pore volumes of water. As a result, it was shown that employing sequential injection allows obtaining an oil recovery factor comparable to that corresponding to oil recovery by nanosuspension. Thus, sequential injection makes it possible to significantly reduce the amount of nanoparticles during injection of nanosuspensions, while maintaining a high beneficial effect on the ORF. This is an important positive fact for the further development of this method of increasing oil recovery.