An insight into a di-chain surfactant adsorption onto sandstone minerals under different salinity-temperature conditions: Chemical EOR applications

Abstract

Surfactant flooding, a chemical enhanced oil recovery (EOR) technique, mainly aims at mobilizing the trapped residual oil by lowering the oil-water interfacial tension. The success of a surfactant flooding operation is strongly affected by surfactant loss through its adsorption on reservoir minerals. Therefore, the adsorption behavior of surfactants is of great importance and needs to be carefully investigated. The present study provides an insight into the adsorption behavior of a recently proposed surfactant, namely Aerosol-OT, on a number of minerals — including quartz-sand, kaolinite, illite, and montmorillonite — under different salinities and temperatures. The examination was carried out in the form of batch experiments, and the surface tension technique was implemented to determine the adsorption rate. The adsorption equilibrium data were examined through two adsorption isotherm models known as Langmuir and Freundlich. It was found that the adsorption rate increased with the increasing salinity, where the highest value was observed for kaolinite (21 g/kg). However, an opposite trend occurred for temperature with the lowest adsorption rate (1.68 g/kg) was obtained for quartz-sand at 85 °C. The adsorption rate of Aerosol-OT was found to be higher than the conventional surfactants. A good correlation was seen between the equilibrium adsorption data and Langmuir isotherm model as their correlation coefficient () exceeded 0.999. The results provide a useful tool to screen surfactants for the chemical EOR operation in clay-rich reservoirs.