A role of ultrasonic frequency and power on oil mobilization in underground petroleum reservoirs

In oil industry, the reduction of oil production is of major concern as world's necessity for oil increases. Therefore, developing and applying new techniques to mobilize residual oil left in the reservoir is important. Ultrasound technique is one of the unconventional methods to increase the productivity of oil wells, but in spite of many laboratory experiments on oil mobilization under ultrasound in porous media the precise mechanisms are weakly understood. Therefore, it is vital to perform basic experiments to achieve a good knowledge and deep insight into the mechanisms. To recognize the reason why ultrasound is able to mobilize residual oil left in pores, one must remember why oil droplet is trapped. Residual oil is left in pores because of insisting capillary forces. So, in this paper a mechanism related to capillary forces are developed to clarify the effect of ultrasound on mobilization of residual oil in porous media. In addition, some experiments are conducted with a 2D glass micro-model in which the mobilization of oil is observed using a digital microscope and camera. It was concluded from the result of experiments that the oil mobilization was proportional to ultrasound power and frequency