Adsorption of aerosol-OT on sand and shale at high sodium salt concentration

Abstract

Surfactant flooding is a method for additional recovery of oil from partially depleted reservoirs by changing the interfacial tension. During the application of surfactant into a reservoir, a certain loss in the high equivalent weight fraction occurs. These surfactant molecules are the most efficient in lowering the interfacial tension between reservoir brine and crude oil. Introducing the surfactant to rock sediment may result in these losses and increase the partition or adsorption of hydrocarbon organic compounds (HOCs) in the rock-water system. The adsorptive behaviour of Aerosol-OT was studied under high salt concentration at room temperature in the presence of sandstone and shale. This study detected the adsorption based on the monitored changes in the initial concentration of the surfactant. The adsorption of the surfactant Aerosol-OT has been investigated using batch adsorption isotherms and the technique of UV-Vis spectroscopy. The objective of the study was to gain further insight into the surfactant adsorption for these adsorbents and to determine the appropriate isotherm model. The equilibrium results showed that the value of concentration changed from 0.03 g/L to the lowest value of 0.0124 g/L, which is lower than half. The batch adsorption isotherms that Aerosol-OT adsorption behaviour followed was found to fit Langmuir-Frandluich model.