Stability Modeling of Water-Based Surfactant Covered Micro-bubble Fluids

Currently, due to the decrease in easy access to crude oil reservoirs, oil and gas industries have focused on production from heavy oil and depleted reservoirs. In recent years, micro‐bubble fluids with surfactant and polymer layers around the bubbles are investigated as a part of drilling fluids and their positive effect on the formation damage is proven. Stability of the bubbles in the fluid is very important, and the optimum surfactant and polymer types should be chosen at optimum concentrations. In this work, an attempt is made to analyze the stability of bubbles of the drilling fluid, based on the diffusive mass transfer concept. Mass transfer and interfacial mass transfer coefficients become more important when surfactant concentration gradient exists in micro‐bubble layers. Interfacial mass transfer coefficients have an important effect on mass transfer phenomena in Aphron fluids system; so, the precise selection of these coefficients results in the conformity of modeling and experiments. We can say that reducing the mass transfer rate from bubble layers will result in stable bubbles in the fluid and, thus, the efficiency of the fluid during drilling will not decrease. It is shown that the interfacial mass transfer coefficient decreases with an increase in surfactant concentration.