大多数碳酸盐岩储层都是油湿/混合湿的，并且在多个尺度上都是非均质的。由于较高的负毛细管压力（ P c ） ，大部分注入水流经高渗透区域和裂缝并绕过基质中的石油。为了提高此类油藏的石油采收率，应通过润湿性改变（WA）来改变P c的符号，或者应通过降低界面张力（IFT）来降低P c 。在整篇论文中，通过对目标碳酸盐岩储层的实验室测量，确定了可以改变润湿性或产生超低界面张力的表面活性剂。
首先进行了接触角、界面张力、相行为和吸入测试，并确定了可以改变润湿性或产生超低界面张力的表面活性剂。然后，利用商业油藏模拟软件建立了实验室规模的渗吸模型。进行了敏感性研究，以评估残余油饱和度（S或）、P c和相对渗透率（K r）的变化、IFT 和基质规模对表面活性剂采收率的影响。
Most carbonate reservoirs are oil-wet/mixed-wet and heterogeneous at multiple scales. The majority of the injected water flows through the high-permeability regions and fractures and bypasses the oil in the matrix because of high negative capillary pressure (Pc). To enhance oil recovery from such reservoirs, the sign of the Pc should be changed by wettability alteration (WA) or the Pc should be reduced by lowering interfacial tension (IFT). In the complete paper, surfactants that can either alter wettability or develop ultralow IFT were identified through laboratory measurements for the target carbonate reservoir.
Contact-angle, IFT, phase-behavior, and imbibition tests were first performed, and surfactants that can either alter wettability or develop ultralow IFT were identified. Then, a laboratory-scale imbibition model was built with commercial reservoir simulation software. A sensitivity study was performed to evaluate the effects of residual oil saturation (Sor), alteration of Pc and relative permeability (Kr), IFT, and matrix scale on oil recovery by surfactant.
