Thermodynamic analysis of adsorption of a naturally derived surfactant onto shale sandstone reservoirs

摘要

Increasing oil recovery from depleted sandstone reservoirs with a low degree of pressure can become possible through performing different chemical methods, particularly polymer-surfactant flooding. Nevertheless, high prices of chemical additives and losing surfactants because of their adsorption on reservoir rocks have always been matters of consideration in this modern EOR solution. In this paper, the adsorption behavior in a system including two phases of gathered porous samples, mainly composed of shale-sandstone and the aqueous solution of an extracted surfactant from Zizyphus spina-christi, has been studied to examine the adsorption thermodynamic and isotherm models of the proposed surfactant. Effects of different surfactant concentration in different temperature on surfactant adsorption density have been analyzed in a batch system. Based on the established conductivity method, the adsorption of the introduced surfactant in a variety of conditions was measured and assessed. It was clear that a higher temperature results in a lower adsorption of the addressed derived natural surfactant from Zyziphus spina-christi on the porous samples. Also, an equilibrium time of ten days was roughly recorded for the crushed rocks. Both Freundlich and Langmuir isotherms performed a high level of compatibility with data belonging to sub-micelle concentration. All in all, the outputs of the performed investigation can be taken as guidelines to select the most appropriate surfactant efficiently for enhanced oil recovery (EOR).