Yekeen Nurudeen, Malik Azlinda Abdul, Idris Ahmad Kamal, Reepei Nadia Izwani, Ganie Kenny
Institute of Hydrocarbon Recovery, Universiti Teknologi PETRONAS, 32610, Bandar Seri Iskandar, Perak, Malaysia.
Department of Chemical & Petroleum Engineering, Faculty of Engineering, Technology and Built Environment, UCSI University, 56000, Kuala Lumpur, Malaysia.
J Pet Sci Eng. 2020 Dec;195:107591. doi: 10.1016/j.petrol.2020.107591. Epub 2020 Jul 4.
In this study, a natural surfactant, saponin was isolated from soapnut (). The extracted surfactant was characterized by Fourier-transform infrared spectroscopy (FTIR) analysis. The effectiveness of the isolated surfactant as EOR agent was evaluated from foam generation/stabilization properties, wettability alteration of the rock surfaces, as well as oil-water interfacial tension (IFT) reduction characteristics. The performance of the extracted saponin was compared with that of a commercial saponin and sodium dodecyl sulfate (SDS). The foaming properties of the saponin with carbon dioxide (CO) was characterized using Teclis Foamscan instrument at room condition and 60 °C. The IFT and contact angles at room conditions and reservoir conditions were measured using KRŰSS Drop Shape Analyzer (DSA 25 and DSA 100) via pendant drop and sessile drop techniques respectively. The foamability of the saponin-stabilized foam was good at ambient condition and 60 °C. Moreover, the time taken for almost 100% liquid drainage was higher in saponin-stabilized foam than the SDS-stabilized foam. The optimum concentration for attaining maximum foam stability decreased from 0.4 wt% at room temperature to 0.1 wt% at 60 °C. Signifying that the quantity of the surfactant to be used in foam generation could reduce at high temperature. The isolated saponin exhibited relatively good interfacial activities individually and in synergistic interaction with silicon dioxide (SiO) nanoparticles at reservoir conditions. Precisely, at 8 MPa and 80 °C, the crude-oil water IFT was reduced from 23.24 mN/m to 1.59 mN/m (about 93.2%) by 0.2 wt% saponin concentration. The IFT was further reduced to 0.87 mN/m (about 96.3%) by a mixed system of 0.5 wt% saponin and 0.05 wt% SiO nanoparticles concentration. Increasing IFT with increasing temperature were observed at very high temperature due to phase separation resulting from clouding phenomenon. However, the clouding temperature increased with 0.1 wt% saponin concentration, and in presence of SiO nanoparticles (0.05 wt% and 0.1 wt%). The study suggests that the extracted saponin could be considered as supplementary alternative to conventional EOR surfactants.
在本研究中，从无患子中分离出一种天然表面活性剂——皂苷。采用傅里叶变换红外光谱（FTIR）分析对提取的表面活性剂进行了表征。从泡沫产生/稳定性、岩石表面润湿性改变以及油水界面张力（IFT）降低特性等方面评估了分离出的表面活性剂作为提高采收率（EOR）剂的有效性。将提取的皂苷性能与市售皂苷和十二烷基硫酸钠（SDS）的性能进行了比较。使用Teclis Foamscan仪器在室温及60°C条件下对皂苷与二氧化碳（CO₂）的发泡性能进行了表征。分别采用悬滴法和座滴法，使用KRŰSS滴形分析仪（DSA 25和DSA 100）测量了室温及油藏条件下的IFT和接触角。皂苷稳定泡沫在环境条件和60°C时的发泡性良好。此外，皂苷稳定泡沫中几乎100%液体排液所需时间比SDS稳定泡沫更长。达到最大泡沫稳定性的最佳浓度从室温下的0.4 wt%降至60°C时的0.1 wt%。这表明在高温下用于产生泡沫的表面活性剂用量可以减少。在油藏条件下，分离出的皂苷单独以及与二氧化硅（SiO₂）纳米颗粒协同相互作用时均表现出相对良好的界面活性。具体而言，在8 MPa和80°C时，0.2 wt%的皂苷浓度可使原油-水IFT从23.24 mN/m降至1.59 mN/m（约93.2%）。0.5 wt%的皂苷和0.05 wt%的SiO₂纳米颗粒浓度的混合体系可使IFT进一步降至0.87 mN/m（约96.3%）。在非常高的温度下，由于浊点现象导致相分离，观察到IFT随温度升高而增加。然而，浊点温度随0.1 wt%的皂苷浓度以及存在SiO₂纳米颗粒（0.05 wt%和0.1 wt%）而升高。该研究表明，提取的皂苷可被视为传统EOR表面活性剂的补充替代品。
