Mechanism Study of Aging Oil Demulsification and Dehydration Under Ultrasonic Irradiation

Abstract

With the tertiary oil recovery in the oilfield, the content of aging oil emulsion with high water content and complex components will gradually increase, so it is crucial for aging oil to break the emulsification. In this paper, the experimental laws of water content are explored under the conditions of different transducer input power through the ultrasonic reforming of aging oil, and the microscopic topography, particle size, components, etc. of oil samples before and after the irradiation of ultrasound are characterized through the microscopic analysis, particle size analysis and component analysis and other ways. The results show that the oil samples achieve the effect of demulsification and dehydration in the presence of ultrasonic cavitation effect, the highest dehydration rate reaches 98.24%, and the dehydration rate shows an "M-type" trend with the increase of power. The results of microscopic analysis and particle size analysis show that ultrasonic irradiation destabilizes the oil-water interfacial membrane, and droplets of different sizes collide, agglomerate, and settle. Moreover, the droplets of the emulsion system are more evenly distributed and the intervals are increased. In addition, the increase in the content of heavy components of oil samples after ultrasound means that the emulsion system appears to be more stable after the reduction of moisture content.

Keywords: Ultrasound, Aging oil, Demulsification, Dehydration, Acoustic cavitation, Mechanism