EFFECT OF COBALT SUBSTITUTION ON THE SATURATION MAGNETIZATION OF MAGNETITE FOR ENHANCED OIL RECOVERY

In conventional EOR, polymer injection into oil reservoir increases viscosity of the injection water for an improved mobility ratio and sweep efficiency. However, it is chemically and thermally unstable above 100°C thus, loses its viscosity. Magnetite nanofluid offers better option with tunability feature a polymer does not have. Though numerous studies on viscosity enhancement of magnetite dispersion as EOR displacing fluid, none of them were looking into the properties affecting magnetoviscosity. High saturation magnetization, Ms and magnetic field strength, H provides greater magnetoviscosity which lead to better sweep efficiency. Therefore, this study is focusing on improving Ms of magnetite by cation substitution and heat treatment to induce cation redistribution and lattice modification among octahedral and tetrahedral sites of magnetite’s inverse spinel structure for a stronger super exchange interaction. Cobalt-substituted magnetite, CoxFe3-xO4 were synthesized via co-precipitation method by varying Co2+ concentration (0≤x≤1) and annealed in argon at 600-800°C. Via X-ray diffraction, Fd-3m cubic spinel structures along with oxides of Fe and Co were identified.