Different types of surfactants are used in the chemical water flooding process in oil reservoirs with the aim of water-oil interfacial tension (IFT) reduction. Recently, much attention is paid to the use of natural surfactants such as plant extracts in enhanced oil recovery (EOR) process. However, some characteristics of these surfactants, such as their efficiencies in achieving the appropriate values of IFT, adaptability to different salinities and their temperature stability at reservoir conditions, must be acceptable. In the current work, a non-ionic surfactant was extracted from Soapwort plant under ultrasonic extraction and saponin purification processes. Proton Nuclear Magnetic Resonance (¹HNMR), Fourier Transform Infrared Spectroscopy (FTIR) and Thermal Gravimetric Analysis (TGA) techniques were used to investigate the natural surfactant characteristics. The pendant drop surface tension tests were used to estimate the critical micelle concentration (CMC) of this natural surfactant. Finally, the application of the surfactant in the EOR process was demonstrated using the experiments of water-oil IFT, contact angle and alkali-surfactant-polymer (ASP) slug injection. The effects of different salinities on surfactant performance in reducing interfacial tension and contact angle were also investigated. Based on the results, the CMC of the surfactant was obtained at 2250 ppm at 80 °C. The water-oil IFT at surfactant CMC was 0.832 mN/m, which decreased by 0.541, 0.714 and 0.775 mN/m at the optimal salinity of the diluted formation water, MgCl₂ and NaCl solutions, respectively. The IFT was decreased by 0.047, 0.078 and 0.096 mN/m at the optimal concentration of NaOH, Na₂CO₃ and NaHCO₃ alkalis, respectively. Sandstone wettability was altered from hydrophobicity to hydrophilicity by surfactant solution at CMC and the contact angle was decreased from 124.42° to 45.94°. The contact angle at CMC was decreased by 35.12°, 38.44° and 43.62° at the optimal concentration of FW, MgCl₂ and NaCl, respectively and eventually, oil recovery was achieved by 32.1% by tertiary ASP slug injection containing surfactant at CMC, optimal saline, optimal NaOH alkali concentration and 1000 ppm of partially hydrolyzed polyacrylamide (PHPA). Surfactants are used in various applications in the oil industry. The focus of this study was on the use of the plant surfactant in EOR by ASP injection process. However, other applications of this surfactant for injection in various scenarios based on chemical water in EOR and other petroleum industries can be developed.

为了降低水油界面张力（IFT），在油藏的化学注水过程中使用了不同类型的表面活性剂。最近，人们非常关注在提高采油率（EOR）过程中使用天然表面活性剂（例如植物提取物）。但是，这些表面活性剂的某些特性，例如获得适当IFT值的效率，对不同盐度的适应性以及它们在储层条件下的温度稳定性，必须是可以接受的。在当前的工作中，通过超声波提取和皂苷纯化工艺从肥皂草植物中提取了一种非离子表面活性剂。质子核磁共振（¹HNMR），傅立叶变换红外光谱（FTIR）和热重分析（TGA）技术用于研究天然表面活性剂的特性。悬滴表面张力测试用于估计该天然表面活性剂的临界胶束浓度（CMC）。最后，通过水-油IFT，接触角和碱-表面活性剂-聚合物（ASP）块塞注入的实验证明了表面活性剂在EOR过程中的应用。还研究了不同盐度对降低界面张力和接触角的表面活性剂性能的影响。基于该结果，在80℃下以2250ppm获得了表面活性剂的CMC。在稀释的地层水的最佳盐度下，表面活性剂CMC处的水油IFT为0.832 mN / m，分别降低了0.541、0.714和0.775 mN / m。₂和NaCl溶液。在NaOH，Na ₂ CO ₃和NaHCO ₃碱的最佳浓度下，IFT分别降低了0.047、0.078和0.096 mN / m 。在CMC下，通过表面活性剂溶液使砂岩的润湿性从疏水性变为亲水性，并且接触角从124.42°减小至45.94°。在FW，MgCl ₂的最佳浓度下，CMC的接触角分别减小了35.12°，38.44°和43.62°。最终通过在CMC处含有表面活性剂，最佳盐水，最佳NaOH碱浓度和1000 ppm部分水解聚丙烯酰胺（PHPA）的三次ASP塞料注入，油的采收率提高了32.1％。表面活性剂被用于石油工业的各种应用中。这项研究的重点是通过ASP注入工艺在EOR中使用植物表面活性剂。然而，在EOR和其他石油工业中基于化学水的各种情况下，这种表面活性剂用于注射的其他应用也可以开发。