Experimental investigation of interfacial properties in the EOR mechanisms by the novel synthesized Fe3O4@Chitosan nanocomposites

Nanoparticles (NPs) have been considerably noticed in the oil and gas industries and mainly in the enhanced oil recovery (EOR) methods. They actually enhance the reservoir characteristics by their unique properties. In this research, the Fe3O4@Chitosan nanocomposites were synthesized in the laboratory and investigated for potential EOR effects for the first time. For this purpose, various static and dynamic experiments, including contact angle, zeta potential, absorbance spectroscopy, oil viscosity, interfacial tension (IFT), and carbonate sand pack flooding were conducted for different concentrations of nanocomposites in the seawater. The zeta potential and absorbance measurements indicate a good stability condition for the synthesized nanocomposite in the seawater during dynamic experiments. The results on contact angle measurements indicate a reduction of 42-53 degrees for 0.01, 0.02, and 0.03 wt.% nanocomposites in the seawater at ambient conditions, which results from the accumulation of the nanocomposites in the vicinity of rock surface and overcoming the available adhesion force between crude oil drop and rock surface. Based on the results from IFT measurements, the reduction of IFT between seawater and crude oil with the increase in temperature and concentration of nanocomposites is clear, which results from asphaltene adsorption onto the surface of the synthesized nanocomposites. What's more, the addition of the synthesized nanocomposite into the crude oil led to the viscosity reduction by 103 cp, which is the key factor in the diminution in the oil viscous forces, improved mobility ratio, and hence the enhanced oil recovery. In the end, an increase of 10.8% improved oil recovery for 0.03 wt.% of nanocomposites was observed in the flooding experiments, compared to the seawater injection, which actually results from a series of EOR mechanisms have been revealed for the synthesized nanocomposite discussed above.