Low‐salinity surfactant (LSS) flooding is a combined enhanced oil recovery (EOR) technique that increases oil recovery (OR) by altering the rock surface wettability and reducing oil–water interfacial tension (IFT). In this study, optimum concentrations of several types of salt in distilled water were obtained on the basis of IFT experiments for the preparation of low‐salinity water (LSW). Then, a new oil‐based natural surfactant (Gemini surfactant, GS) was combined with LSW to investigate their effects on IFT, wettability, and OR. Experimental results showed that LSW is capable of reducing IFT and contact angle, but the synergy of GS and the active ions Mg²⁺, Ca²⁺, and SO₄²⁻ in LSW was more effective on IFT reduction and wettability alteration. The combination of 1000 ppm MgSO₄ and 3000 ppm GS led to a decrease in contact angle from 134.82° to 36.98° (oil‐wet to water‐wet). Based on core flooding tests, LSW injection can increase OR up to 71.46% (for LSW with 1000 ppm MgSO₄), while the combination of GS and LSW, as LSS flooding, can improve OR up to 84.23% (for LSS with 1000 ppm MgSO₄ and 3000 ppm GS). Therefore GS has great potential to be used as a surfactant for EOR.

中文翻译：

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使用新型双子表面活性剂系列非离子油基表面活性剂和低盐度水的界面张力降低，润湿性变化和油采收率的研究：油湿碳酸盐岩的实验研究

低盐度表面活性剂（LSS）驱油是一种组合的强化采油（EOR）技术，可通过改变岩石表面的润湿性和降低油水界面张力（IFT）来提高采油量（OR）。在这项研究中，根据用于制备低盐度水（LSW）的IFT实验获得了蒸馏水中几种盐的最佳浓度。然后，将一种新型的油基天然表面活性剂（Gemini表面活性剂，GS）与LSW结合使用，以研究它们对IFT，润湿性和OR的影响。实验结果表明，LSW能够降低IFT和接触角，但是GS与活性离子Mg 2 ⁺，Ca ²⁺和SO ₄ ^2-的协同作用在LSW中，使用ISC在降低IFT和改变润湿性方面更有效。1000 ppm MgSO ₄和3000 ppm GS的组合导致接触角从134.82°减小到36.98°（油湿到水湿）。根据岩心驱替测试，LSW注入可使OR高达71.46％（对于含1000 ppm MgSO _4的LSW而言），而GS和LSW的组合作为LSS驱使可提高OR高达84.23％（针对LSPS达1000 ppm的情况） MgSO ₄和3000 ppm GS）。因此，GS具有用作EOR的表面活性剂的巨大潜力。