Novel enhanced oil recovery method using dielectric zinc oxide nanoparticles activated by electromagnetic waves

Abstract

Deep water oil reservoirs buried more than 500m possess high temperature and high pressure conditions, which caused failure to most of the oil recovery methods involving fluid injection. A non-invasive electromagnetic (EM) wave transmission system coupled with nanofluid injection has been proposed to improve recovery factor of an oil reservoir. Interactions of the dielectric nanoparticles at low frequency radio wave range are mainly ionic and interfacial polarization, which could be manipulated to disturb the compatibility at oil-water interfaces. An attempt to measure oil recovery due to interaction of EM waves with dielectric nanoparticles has been performed. In this work, zinc oxide, ZnO nanoparticles synthesized via sol-gel method formed single phase hexagonal wurzite structure at temperature 300°C. As confirmed by X-ray diffraction (XRD), average ZnO crystals size was 45nm, with the major growth in [100] direction. ZnO nanofluid was prepared by dispersing ZnO nanoparticles in deionized water and ultrasonicated for 2 hours, which was then injected into a packed glass bead column of 24 cm length and having permeability of 380 mD, to replicate the reservoir material. Prior to this injection, the column was saturated with Arabian Heavy crude oil of viscosity 16.31 cp at 25°C, followed by water flooding to recover 71% of the original oil in place (OOIP). After 30 minutes exposure to electromagnetic wave radiation and nanofluid injection simultaneously, it has successfully recovered 26% of the remaining oil. It is expected that interaction between EM waves and ZnO nanoparticles in the column will induce atomic vibration on the pore surfaces and as a consequence, released the trapped oil.