The Synergistic Effect of a Mixed Surfactant (Tween 80 and SDBS) on Wettability Alteration of the Oil Wet Quartz Surface

The synergistic effect of a new combination of Tween 80 and sodium dodecylbenzenesulfonate (SDBS) surfactants has been studied for wettability alteration of a reservoir rock. The contact angle decreased substantially for the aqueous solution of the mixed surfactant on a crude oil aged quartz substrate when compared to water and individual surfactants viz. SDBS and Tween 80. This established synergism between anionic and non-ionic surfactants. The optimal salinity for reduction of the contact angle has been figured out. The rheological effect of the mixed surfactant solution on the wettability alteration has been investigated. Adsorption of crude components at the solid–fluid interfaces has been observed to visualize the activity at the micro scale. Quantification of adsorption for the mixed surfactant on sand has been studied to meet the economical aspect. Reaction aspects of the mixed surfactant–quartz–crude oil system have been interpreted from FTIR. Functional groups present in the system have also been enquired.