Effect of ultrasound radiation duration on emulsification and demulsification of paraffin oil and surfactant solution/brine using Hele-shaw models

Abstract

Ultrasound technique is one of the unconventional enhanced oil recovery methods which has been of interest for more than six decades. However, the majority of the oil recovery mechanisms under ultrasound reported in the previous studies are theoretical. Emulsification is one of the mechanisms happening at the interface of oil and water in porous media under ultrasound. Oppositely, ultrasound is one of the techniques using in oil industry for demulsification of oil/water emulsion. Therefore, the conditions in which emulsification becomes dominant over demulsification under ultrasound should be more investigated. Duration of ultrasound radiation could be one of the factors affecting emulsification and demulsification processes. In this study a technique was developed to investigate the effect of long and short period of ultrasound radiation on emulsification and demulsification of paraffin oil and surfactant solution in porous media. For this purpose, the 2D glass Hele-shaw models were placed inside the ultrasonic bath under long and short period of radiation of ultrasound. A microscope was used above the model for microscopic studies on the interface of oil and water. Diffusion of phases and formation of emulsion were observed in both long and short period of application of ultrasound at the beginning of ultrasound radiation. However, by passing time, demulsification and coalescence of brine droplets inside emulsion was initiated in long period of ultrasound application. Therefore, it was concluded that emulsification could be one of the significant oil recovery mechanisms happening in porous media under short period of application of ultrasound.

Ultrasound-assisted CO2 flooding to improve oil recovery

“…Also it was noted that energy through these sources may help to have an efficient oil-water de-emulsification process [24] [25] [26]. The aim of these methods is to deliver an external energy into oil through waves.…”

“…In fact, ultrasound reduces interfacial tension (IFT) and reservoir oil viscosity, and increases medium temperature, which in turns enhance the displacement efficiency [28,26,29].…”

“…A reduction in water cut (20 %) and an increase in oil production up to 91% was reported after the treatment. In recent years, Hamidi and his co-workers [28,26,34,35] performed several experiments to study oil recovery mechanisms under influence of ultrasound in porous media. They found that heat generation, emulsification, cavitation, and the reduction of oil viscosity are the most important mechanisms that improve oil recovery factor under the influence of ultrasound.…”

“…In other studies by Hamidi et al. [26], they developed a technique to investigate the effect of ultrasound radiation at the interface of oil and brine in porous media using a microscope. Diffusion of phases and generation of emulsion were disclosed in the period that ultrasound was applied.…”

Effects of ultrasonic waves on carbon dioxide solubility in brine at different pressures and temperatures

“…Then, one might expect the propagation of ultrasonic waves in the subsurface environment while sending low-frequency elastic waves from the surface (seismic) or due to earthquake nonlinear plane waves (Naderi and Babadagli 2010). A large number of studies have been conducted on the effects of ultrasound on enhanced oil recovery processes, emulsification of oil and brine, oil viscosity, oil mobilization in porous media, phase behaviour of a surfactant-brine-oil system, liquid-liquid interaction, and chemical treatment of horizontal wells (Hamidi et al 2012(Hamidi et al , 2013(Hamidi et al , 2015aBabadagli 2006, 2007;Naderi and Babadagli 2010;Abramov et al 2013Abramov et al , 2015Abramov et al , 2016. All of these studies have shown promising results after applying ultrasonic waves for testing processes.…”