Displacement of oil by different interfacial tension fluids under ultrasonic waves

Insight into the physical principles governing the mobilization of oil by ultrasonic waves is vital for developing novel techniques of oil extraction. Various mechanisms such as peristaltic transport due to mechanical deformation of the pore walls, reduction of capillary forces due to the destruction of surface films, coalescence of oil drops due to the Bjerknes forces, oscillation and excitation of capillary trapped oil drops, forces generated by cavitating bubbles, and sonocapillary effects may be responsible for enhancing the flow of oil through porous media in the presence of an acoustic field. This paper aims at analyzing the influence of high-frequency, high-intensity ultrasonic radiation on the immiscible and miscible displacement. To analyze the viscous displacement under ultrasonic waves, experiments were performed on Hele-Shaw models. Immiscible (for mineral oil-brine and mineral oil-surfactant pairs) and miscible (for mineral oil-pentane, mineral oil-kerosene and mineral oil-2-propanol pairs) displacement experiments were per-formed. Changes on the displacement fronts and patterns were observed under ultrasound. Fractal techniques were used to analyze the changes and correlate them to the intensity of ultrasonic waves. (C) 2007 Elsevier B.V. All rights reserved.