Feasibility Study of Dual-Function Chemical in Reducing Surfactant Adsorption and Interfacial Tension for Chemical Enhanced Oil Recovery Application

Abstract

Summary The performance of a low-cost and biodegradable dual-function chemical was evaluated based on its attainment in reducing the interfacial tension (IFT) and surfactant adsorption in synthetic seawater at a temperature of more than 90°C. The phase behavior, interfacial tension, and static adsorption tests were conducted for the feasibility study of a dual-function chemical for a chemical enhanced oil recovery application. The experimental matrices were constructed using Design Expert (Stat-Ease, Minneapolis, Minnesota, USA). Alkyl ether carboxylate (AEC) and amido propyl betaine (APB) were identified for the study to be tested with the dual-function chemical at a temperature of more than 90°C in synthetic seawater. In the phase behavior study, the volume ratio of the aqueous phase to the Malaysian crude oil was kept 1:1. The interfacial tension between the surfactant and dual-function chemical system against the crude oil was performed by using a spinning drop method. Meanwhile, the static adsorption was conducted by using the crushed core at room temperature for up to 30 days, and the analysis was conducted using a high-performance liquid chromatography method. In comparison with two types of surfactants, the dual-function chemical works best with the AEC surfactant in order to reach an ultralow interfacial tension (less than 10−3 mN/m) within 60 minutes. An ultralow interfacial tension for APB surfactant can only be obtained at an earlier time. In contrast, the phase behavior study for AEC and APB surfactants and dual-function chemical obtained was a Type II(−) microemulsion. In the static adsorption study, the dual-function chemical (>0.5 wt%) significantly helped in reducing the adsorption of AEC and APB surfactants by up to 73%. Based on the obtained results, the dual-function chemical worked more efficiently when compounded with AEC than APB surfactant at the same surfactant concentration and reservoir conditions. The findings of this feasibility study are worthwhile for the potential application of dual-function chemical for chemical enhanced oil recovery.