Novel Enhanced Oil Recovery Method Using Co²⁺_xFe²⁺_1-xFe³⁺₂O₄ as Magnetic Nanoparticles Activated by Electromagnetic Waves

Research on the application of nanoparticles, specifically magnetic nanoparticles in enhanced oil recovery has been increasing in recent years due to their potential to increase the oil production despite having to interact with reservoirs of high salinity, high pressure and temperature and un-natural pH. Unlike other conventional EOR agents e.g. surfactants and polymers, a harsh environment will cause degradation and failure to operate. Magnetic nanoparticles which are activated by a magnetic field are anticipated to have the ability to travel far into the oil reservoir and assist in the displacement of the trapped oil. In this work, ferromagnetic Co²⁺_xFe²⁺_1-xFe³⁺₂O₄ nanoparticles were synthesized and characterized for their morphological, structural and magnetic properties. At a composition x = 0.75, this nanomaterial shows its best magnetisation parameters i.e. highest value of saturation magnetization, remanence and coercivity of 65.23 emu/g, 12.18 emu/g and 239.10 Oe, respectively. Subsequently, a dispersion of 0.01 wt% Co²⁺_0.75Fe²⁺_0.25Fe³⁺₂O₄ nanoparticles in distilled water was used for core flooding test to validate its feasibility in enhanced oil recovery. In a core flooding test, the effect of electromagnetic waves irradiation to activate the magnetization of Co²⁺_0.75Fe²⁺_0.25Fe³⁺₂O₄ nanofluid was also investigated by irradiating a 78 MHz square wave to the porous medium while nanofluid injection was taking place. In conclusion, an almost 20% increment in the recovery of oil was obtained with the application of electromagnetic waves in 2 pore volumes injection of a Co²⁺_0.75Fe²⁺_0.25Fe³⁺₂O₄ nanofluid.