The study of the spontaneous oil imbibition in the presence of new polymer-coated nanocomposites compatible with reservoir conditions

In this study, the effect of salinity on the enhanced oil recovery process in the presence of commercial silica nanoparticles and a new synthesized polymeric ZnO/SiO2/Xhantan nanocomposites (NCs) at reservoir conditions were investigated. First, the crystal structure and morphology of the NCs were investigated using x-ray diffraction, Scanning electron microscopy, Fourier transform infrared spectroscopy, Brunauer–Emmett–Teller, and energy-dispersive x-ray. Then, the effect of silica nanoparticles and NCs on the change of wettability and interfacial tension at different salinities and reservoir conditions was studied. For 2 SW (seawater) and 10 SW (two times diluted seawater), silica and NCs decreased contact angle from (79 °, 75 °) to (78 °, 74 °) and (70 °, 62 °), respectively. Zeta potential results are −31.37 and −28.00 for 10 SW and 2 SW concentrations, which show the perfectly stable and relatively stable regions, respectively. Moreover, interfacial tension was decreased more in the presence of 10 SW in comparison to 2 SW, and the oil recovery at 2 SW and 10 SW concentrations were 51.71% and 70.25%, respectively, at 0.05 wt% NCs concentration which main reasons are improving wettability, interfacial tension, and stability.