Design and Synthesis of New ZnO/Xanthan Nanocomposites Based on Enhanced Oil Recovery (EOR) Application in Carbonate/Sandstone Composite (CSC) Reservoirs

In this study, a new nanocomposite called ZnO /Xanthan NCs was synthesized to improve the mechanism of wettability change and IFT reduction in smart water injection. The characterization of the synthesized NCs was investigated using scanning electron microscopy (SEM), X-ray diffraction (XRD), and Fourier-transform infrared spectroscopy (FTIR). Also, a novel nanocomposite at various concentrations of 100, 200, 400, 700, 1000, and 1500 (ppm) was used as dispersion media. The prepared nano fluid was tested via various experimental methods, such as stability, IFT, PH, and wettability alteration, to find the optimum concentration for carbonate and sandstone rock. Zeta and conductivity values indicate that the optimum value of NCs concentration is 200 ppm. This concentration of solution can reduce the amount of interfacial tension from 35 m N/m to 23 mN/m (about 34/2% IFT reduction) and change the contact angle for sandstone from 142° to 87° and change the contact angle for carbonate from 154° to 61°, respectively. X-ray diffraction was used to show the purity and crystal structure of these particles. Field Emission Scanning Electron Microscopy (FESEM) characterization test provides the surface morphology of the synthesized nanocomposite and the particle size of NCs at approximately 43 to 59 nm. The value of zeta potential at 200 ppm indicates the highest stability among other concentrations. The solution with a concentration of 200 ppm improved oil recovery from 43.11–57.55% in sandstone and 33–46%.