两亲碳点的表界面性能与驱油性能

Surface/Interfacial Properties and Oil Displacement Performance of Amphiphilic Carbon Dots

卢仁玲 赖 璐

LU Renling LAI Lu

高界面活性纳米驱油材料的制备是纳米技术在超低渗透油藏提高采收率中应用的关键问题。考察了自制两亲碳点（CDs）的表界面活性，研究了无机盐和老化温度对两亲 CDs 界面活性的影响，并研究了两亲 CDs 的油膜剥离性能和润湿反转性能，通过岩心驱替实验评价了两亲 CDs 的驱油性能。研究结果表明，两亲 CDs 具有与表面活性剂相似的表面张力曲线，其临界胶束浓度和平衡表面张力分别为150.21 mg/L和28.43 mN/m。在60 ℃、 100 g/L NaCl 和 25 g/L CaCl2条件下仍能保持较高的界面活性，可将油水界面张力由 0.578 mN/m 分别降低至0.032 mN/m 和0.015 mN/m。此外，两亲 CDs 具有优异的油膜剥离性能和润湿反转性能，经两亲 CDs 处理后，油膜面积分别减少了79.3%，并且具有润湿反转能力，可将亲油玻璃片表面的水滴接触角由109.2°降至44.8°。岩心驱油实验表明，在85 g/L NaCl 和10 g/L CaCl2条件下，两亲CDs驱油效率为17.4%，具有较好的耐盐性。因此，两亲CDs作为一种高界面活性的耐高温耐盐纳米颗粒，在高温高盐油藏提高采收率方面具有广阔的应用前景。

The preparation of nano oil displacement materials with high interfacial activity remains a critical issue for the application of nanotechnology in ultra-low-permeability reservoirs to enhance oil recovery. The surface interfacial activity of self-made amphiphilic carbon dots（CDs）and high interfacial activity was investigated. The effects of inorganic salts and aging temperature on the interfacial activity of the CDs were studied，and the oil film removal and wettability alteration properties of the CDs were determined. Finally，the oil displacement efficiency of the CDs was evaluated by the core flooding experiments. The results showed that amphiphilic CDs had similar surface tension curves to surfactants，and the surface tension at critical micelle concentration and surface tension was 150.21 mg/L and 28.43 mN/m，respectively. Furthermore，amphiphilic CDs could maintain high interfacial activity at cNaCl =100 g/L and cCaCl2 =25 g/L，reducing interfacial tension from 0.578 mN/m to 0.032 mN/m and 0.015 mN/m. In addition，amphiphilic CDs had excellent oil film removal efficiency and wettability alteration performance，which could effectively remove residual oil in the form of oil film from the sandstone surface and reduce the contact angle of water droplets in the air from 109.2° to 44.8°. Finally，core flooding experiments showed that the oil displacement efficiency of amphiphilic CDs was 17.4% in the presence of 85 g/L NaCl and 10 g/L CaCl2. Therefore，as temperature-resistant and salt-tolerant nanoparticles with ultra-small size，amphiphilic CDs have broad application prospects in enhancing oil recovery in high-temperature and high-salt reservoirs.

10.19346/j.cnki.1000-4092.2024.03.015