Recently, a non-invasive method of injecting magnetic/dielectric nanofluids into the oil reservoir was used for oil recovery application. The use of magnetic nanofluids in Enhanced Oil Recovery (EOR) has been reported to improve oil recovery. It is believed that the magnetic properties of nanoparticles (NPs) have a direct influence on the viscosity and wettability of nanofluid, and on oil-water interfacial tension (IFT). Thus, Mn0.5Zn0.5Fe2O4 (MnZn) ferrites may be a good candidate to be used in nanofluids for wettability alteration and oil-water IFT reduction due to their excellent magnetic properties, such as a high initial permeability and low magnetic losses. Therefore, this work investigated the potential of MnZn ferrite NPs to alter viscosity, wettability, and oil-water IFT. MnZn Ferrite NPs have been synthesized by a sol-gel auto-combustion process. The effects of calcination temperature varying from 300 °C to 700 °C on the phase formation, microstructures such as surface morphology, and magnetic characterizations were studied. MnZn ferrite nanofluids were prepared using synthesized MnZn NPs that dispersed into brine along with sodium dodecylbenzenesulfonate (SDBS) as a dispersant, and their effects on the wettability and oil-water IFT were studied. X-ray diffraction (XRD) measurements revealed that MnZn ferrite calcined at 300 °C and 400 °C were single phase. The average crystallite size calculated through Scherrer’s equation differed from 32.0 to 87.96 nm. The results showed that the nanofluid with MnZn particles calcined at 300 °C is the best nanofluid in terms of IFT reduction and base nanofluid’s wettability alteration. Moreover, the overall results proved that nanofluid with MnZn ferrite NPs can alter the wettability of base nanofluid, oil-nanofluid IFT, and nanofluid viscosity. This study provides insights towards a better understanding of the potential application of MnZn Ferrite nanofluids to Wettability Alteration and IFT Reduction in Enhanced Oil Recovery.

MnZn Spinel ferrite with the chemical formula of MnxZn1-xFe2O4 (x = 0, 0.25, 0.5, 0.75, 1.0) were synthesized by a sol-gel auto-combustion method. Structural and morphological properties of synthesized samples were characterized by X-ray diffraction (XRD) and Field Emission Microscopy (FESEM). XRD patterns revealed characteristic peaks corresponding to spinel Mn-Zn ferrite structures. In addition, the structural analysis demonstrates that the average crystallite size of the synthesized samples varied in the range of 30.0-40.0 nm. The FESEM micrographs reveal agglomerated particles with particles size ranging from 60-80nm. Interfacial tension (IFT) and contact angle measurement for MnZn ferrite nanofluids were performed. The results showed that the use of MnZn ferrite nanofluid significantly decrease the oil-water IFT and contact angle.