Low salinity water (LSW) flooding alters rock surface wettability toward more water wetness, and consequently, oil recovery will be increased from a carbonate oil reservoir. Surfactant flooding and polymer flooding enhance oil recovery by oil–water interfacial tension (IFT) reduction and water–oil mobility ratio change, respectively. In this study, a combination of LSW and two non-ionic natural surfactants for enhanced oil recovery was evaluated. Four types of salts (CaCl₂, MgCl₂, Na₂SO₄, and MgSO₄) at different concentrations in distilled water were used to find optimal LSW based on contact angle (CA) reduction. Two non-ionic natural surfactants (a new natural surfactant from Gemini surfactants (GS) family and Tribulus terrestris surfactant) were applied to obtain their optimum concentration based on IFT reduction. The minimum IFT was achieved in 2000 ppm of GS (4.06 mN/m) and 3000 ppm of TTS (6.21 mN/m). Experimental results showed that the presence of GS in low salinity surfactant solution (1000 ppm of MgSO₄ and 2000 ppm GS) is capable to reduce IFT (to 1.02 mN/m) and CA (to 31.25°). Therefore, GS showed good results in IFT improvement and wettability alteration. Finally, the optimal LSS was combined with different concentrations of PHPA polymer and injected into cores. Core flooding results demonstrated 69.7% oil recovery for LSW injection, 82.2% for low salinity GS injection (an increase of 12.5%) and 87.9% for low salinity GS-polymer injection (an increase of 5.7%).

低盐度水（LSW）驱替使岩石表面的润湿性向更大的水湿度方向转变，因此，从碳酸盐储油层中采油将增加。表面活性剂驱油和聚合物驱油分别通过降低油水界面张力（IFT）和改变水油流动率来提高采油率。在这项研究中，评估了LSW和两种非离子型天然表面活性剂的组合以提高采油率。四种类型的盐（CaCl ₂，MgCl ₂，Na ₂ SO ₄和MgSO ₄）在蒸馏水中的不同浓度用于根据接触角（CA）的减少找到最佳LSW。两种非离子型天然表面活性剂（来自Gemini表面活性剂（GS）系列的新型天然表面活性剂和Tribulus terrestris表面活性剂）用于根据IFT减少量获得最佳浓度。在2000 ppm的GS（4.06 mN / m）和3000 ppm的TTS（6.21 mN / m）中实现了最小IFT。实验结果表明，低盐度表面活性剂溶液（1000 ppm MgSO ₄GS和2000 ppm GS）能够将IFT（降低至1.02 mN / m）和CA（降低至31.25°）。因此，GS在改善IFT和改变润湿性方面显示出良好的结果。最后，将最佳的LSS与不同浓度的PHPA聚合物混合并注入岩心中。岩心驱油结果表明，低盐度GS注入的油采收率为69.7％，低盐度GS注入的油采收率为82.2％（低盐GS聚合物注入的油采收率为87.9％）（增长5.7％）。