Synthesis and surfactant properties of sulfonate Gemini surfactants

In this study, a novel high salinity resistant, high temperature tolerant sulfonate Gemini surfactant (CK-3) for enhanced oil recovery was synthesized and is described. The critical micelle concentration (CMC) of CK-3 is 7.3 × 10 −5  mol L −1 with a surface tension at CMC, γ CMC , of 30.88 mN m −1 , and a pC 20 value of 4.80. Moreover, increasing temperature led to delayed micellization, indicating the superior surface activity inherent in Gemini surfactants. When CK-3 was evaluated as an imbibing agent, an interfacial tension of 8.3 × 10 −2  mN m −1 was observed between a 0.3 wt% CK-3 solution and crude oil, facilitated by hydrophobic group interactions which allow crude oil detachment. Finally, CK-3 molecules exhibited stable adsorption on rock walls, influencing wetting reversal. Zeta potential measurements exceeding 30 mV indicated stability. In aged capillary tubes, a 0.3 wt% CK-3 solution exhibited a rise height of 2.9 cm. Imbibition experiments on natural core samples showed a water imbibition efficiency of 8.73 %, compared to a significantly improved efficiency of 50.78 % with a 0.3 wt% CK-3 solution. This study also demonstrated the imbibition process and mechanisms of the CK-3, providing novel insights for the efficient development of unconventional oil reservoirs and the enhancement of crude oil recovery rates.