Static and dynamic adsorption of a non-ionic surfactant on Berea sandstone

Abstract

An experimental study of static and dynamic adsorption of a non-ionic surfactant (Triton X-100) on Berea sandstone was conducted. The effects of sodium chloride concentration, pH and injection flow rate on the surfactant propagation were examined. A radial flow geometry was used to simulate the fluid flow pattern near a wellbore. Static adsorption isotherms were of the stepped Langmuir type and exhibited good agreement with the hemimicelle model. Experimental results showed that the adsorption capacity of the solid surface was a strong function of both solution salinity and pH. Maximum adsorption obtained from dynamic tests was consistently lower than that obtained from static tests. The difference increased as the flow rate was increased. The results obtained in this study indicate that the amount of surfactant adsorbed on sandstone decreased under alkaline conditions. This will reduce the amount of non-ionic surfactant required for the application of the alkali/surfactant process in the field. Also, static adsorption tests will tend to overestimate the amount of surfactant lost due to adsorption, especially near the wellbore area.