Surfactants are widely used for enhanced oil recovery (EOR) purposes by reducing interfacial tension (IFT) of oil–water phases and wettability alteration. Some surfactants with viscoelastic properties can be used as mobility control agents due to enhanced viscosity resulting from the spherical-to-cylindrical shape transition of micelles. Dodecyltrimethylammonium chloride (DAC) shows viscoelastic behavior coupled with dominantly cylindrical shape of the micelle in ambient conditions. Nevertheless, using DAC as an IFT reduction and mobility control agent needs to be industrialized for actual operating conditions. In this study, DAC, as a cationic surfactant, was experimentally studied in reservoir conditions considering dominantly cylindrical micelles for the first time. Results showed that the viscosity of DAC solution is a strong function of DAC concentration, especially at high temperature and high salinity conditions, while it does not depend on pressure significantly. Transmission electron microscope (TEM) images were taken for a better understanding of DAC micellar structures. Analysis of the TEM results indicated the shape transition of the micelles from small spherical to large cylindrical at higher concentrations of DAC. IFT of DAC microemulsion was studied for wide ranges of temperature and DAC concentration, ruling out any significant effect of the temperature on the IFT trend line. A general mathematical model for predicting the viscosity of surfactant solution was developed and evaluated for real reservoir conditions by including all effective terms. Results showed a very good agreement with experimental data of DAC and Cetyltrimethyl ammonium bromide (CTAB, as per previous studies), justifying the applicability of the developed model for predicting the viscosity wherever experimental data is unavailable. Core flood tests were performed with saltwater (SW) and DAC solutions with spherical (SS) and cylindrical (SC) micelles as injecting phases for evaluation of IFT reduction and mobility control effects. Results showed an additional recovery factor of 13 % for SS and 23 % for SC in comparison with SW injection.

表面活性剂通过降低油水相的界面张力（IFT）和润湿性改变而广泛用于提高采收率（EOR）目的。一些具有粘弹性的表面活性剂可以用作流动性控制剂，因为胶束从球形到圆柱形的形状转变导致粘度增加。十二烷基三甲基氯化铵 (DAC) 在环境条件下表现出粘弹性行为以及胶束的主要圆柱形形状。然而，使用DAC作为IFT降低剂和流动性控制剂需要针对实际操作条件进行工业化。在这项研究中，DAC作为一种阳离子表面活性剂，首次在考虑以圆柱形胶束为主的储层条件下进行了实验研究。结果表明，DAC 溶液的粘度是 DAC 浓度的强函数，尤其是在高温和高盐度条件下，而与压力的关系不大。拍摄透射电子显微镜 (TEM) 图像是为了更好地了解 DAC 胶束结构。 TEM 结果分析表明，在较高浓度的 DAC 下，胶束的形状从小球形转变为大圆柱形。在较宽的温度和 DAC 浓度范围内研究了 DAC 微乳液的 IFT，排除了温度对 IFT 趋势线的任何显着影响。通过包含所有有效项，开发了用于预测表面活性剂溶液粘度的通用数学模型，并针对实际储层条件进行了评估。结果显示与 DAC 和十六烷基三甲基溴化铵（CTAB，根据之前的研究）的实验数据非常吻合，证明了所开发的模型在无法获得实验数据的情况下预测粘度的适用性。使用盐水 (SW) 和 DAC 溶液进行岩心驱替试验，以球形 (SS) 和圆柱形 (SC) 胶束作为注入相，以评估 IFT 降低和流度控制效果。结果显示，与 SW 注射相比，SS 的额外回收系数为 13%，SC 的回收系数为 23%。