an estimation of wave attenuation factor in ultrasonic assisted gravity drainage process

it has been proved that ultrasonic energy can considerably increase the amount of oil recovery in animmiscible displacement process. although many studies have been performed on investigating theroles of ultrasonic waves, based on the best of our knowledge, little attention has been paid to evaluatewave attenuation parameter, which is an important parameter in the determination of the energydelivered to the porous medium. in this study, free fall gravity drainage process is investigated in aglass bead porous medium. kerosene and dorud crude oil are used as the wetting phases and air isused as the non-wetting phase. a piston-like displacement model with considering constant capillarypressure and applying corey type approximation for relative permeabilities of both wetting and nonwettingphases is applied. a pressure term is considered to describe the presence of ultrasonic wavesand the attenuation factor of ultrasonic waves is calculated by evaluating the value of externalpressure applied to enhance the flow using the history matching of the data in the presence andabsence of ultrasonic waves. the results introduce the attenuation factor as an important parameter inthe process of ultrasonic assisted gravity drainage. the results show that only a low percentage of theultrasonic energy (5.8% for dorud crude oil and 3.3% for kerosene) is delivered to the flow of thefluid; however, a high increase in oil recovery enhancement (15% for dorud crude oil and 12% forkerosene) is observed in the experiments. this proves that the ultrasonic waves, even when thecontribution is not substantial, can be a significantly efficient method for flow enhancement.