纳米SiO₂ 微乳液对鄂南致密油藏的降压增注效果

Effect of Nano-SiO₂ Microemulsion on Pressure Reduction and Injection Increase in Eunan Tight Reservoir

吴可 文守成 邵伟 许明标

WU Ke WEN Shoucheng SHAOWei XU Mingbiao

红河油田长8 油藏断裂结构复杂，属于低孔超低渗油藏，储层非均质性强，且基质残余油饱和度高，水相渗 透率低，注水压力上升速度快，已超过裂缝重启压力，水窜现象严重，注水开发效果差。结合纳米粒子与微乳液 特性设计了一种纳米SiO2微乳液降压增注体系，系统评价了该体系耐温性、降低界面张力能力、增溶性及与地层 配伍性，并开展了岩心降压增注驱替实验。实验结果表明，该纳米SiO2微乳液体系不仅抗温、抗盐性良好，且界 面活性高，油水界面张力可降至10-2 mN/m左右；纳米SiO2微乳液体系的油增溶性能良好，增溶量达到6.5 mL/30 mL。岩心降压增注实验结果显示，向水测渗透率约为0.4×10-3 μm2的岩心中注入2 PV 质量分数为1%的纳米 SiO2微乳液体系，降压效率达到28%以上，降压增注效果明显，能满足现场需求。

The fracture structure of the Chang 8 reservoir in the Honghe oilfield is complex，which belongs to a low porosity and ultra-low permeability reservoir. The reservoir heterogeneity is strong and the residual oil saturation is high. Because the water phase permeability is low，and the water injection pressure rises rapidly，which exceeds the fracture restart pressure，resulting in serious water channeling and poor effect of water injection development. Combined with the characteristics of nano and microemulsion，a nano-SiO2 microemulsion depressurization and injection-augmenting system was designed，and the temperature resistance， interfacial tension reduction ability，solubilization and formation compatibility of the system were systematically evaluated，and the core depressurization and injection-augmenting displacement experiment was carried out. The experimental results demonstrated that the nano-SiO2 microemulsion system not only exhibited excellent temperature resistance and salt resistance but also possessed high interfacial activity，reducing the oil-water interfacial tension to approximately 10-2 mN/m. The system showed good oil solubilization performance with a solubilization amount of 6.5 mL/30 mL. Simultaneously，the core pressure reduction and injection increase experiment indicated that after injecting 2 PV of 1% the nano-SiO2 microemulsion system into the cores with the permeability of 0.4 × 10-3 μm2， the pressure reduction efficiency exceeded above 28% . The depressurization and injection-augmenting effects of the system were evident，meeting the requirements of the field.

10.19346/j.cnki.1000-4092.2024.02.008