Experimental investigation of a natural surfactant adsorption on shale-sandstone reservoir rocks: Static and dynamic conditions

In order to increase the oil recovery factor from depleted sandstone reservoirs with low degree of pressure, implementation of chemical flooding is the technically known as a feasible solution. The polymer-surfactant flooding, as one of the main subsets of chemical flooding methods, is a vigorous Enhanced Oil Recovery (EOR) method which can be applied with a high level of performance in sandstone reservoirs. Applying the aforementioned technique is very often unfeasible due to the expensive chemical additives and surfactant loss in term of adsorption on the reservoir rock. This paper mainly deals with the adsorption behavior (both static and dynamic) of the natural surfactant, which extracted surfactant from leaves of Zyziphus Spina Christi, onto a real shale-sandstone reservoir samples. Furthermore, adsorption kinetics and equilibrium are determined to help the understanding of the adsorption mechanism. To examine the effect of adsorbent dose on the adsorption efficiency, static adsorption experiments are performed. The effect of temperature on the kinetic and equilibrium of adsorption process was experimentally done. Finally, two core flooding experiments are carried out to determine the adsorption behavior in dynamic conditions. It was emerged that the Freundlich model has a more permissible fit for the adsorption equilibrium of natural surfactant after analyzing the related data for four models. Moreover, the laboratorial research about the adsorption kinetics proved statistically that pseudo-second order model prepares the best kinetics model for the natural surfactant. (C) 2015 Elsevier Ltd. All rights reserved.