纳米淀粉流体提高原油采收率

Enhanced Oil Recovery of Nano-starch Fluid

王成俊 周文佳 郑江波 展转盈 张 磊

WANG Chengjun ZHOU Wenjia ZHENG Jiangbo ZHAN Zhuanying ZHANG Lei

为了进一步促进纳米驱油技术在低渗透油藏中的高效应用，亟需开发新型的纳米驱油产品。纳米淀粉颗 粒作为一种环境友好型的材料，分布广、价格相对低廉、性能优异，具备大幅度提高采收率的潜力。通过室内静 态实验、岩心驱替实验、微观可视化实验、CT扫描实验等手段，从纳米淀粉流体的基本物性、提高驱油效果、扩大 波及体积等方面研究了其提高采收率的过程和机理。研究结果表明，质量浓度为5000mg/L的纳米淀粉流体因 其亲水性和较小的粒径（30nm）可改变水分子的赋存状态，使水相变温度从102℃升高至110℃，使得岩石表面 的润湿接触角从78°降至34.2°，使油水界面张力从20mN/m降至0.56mN/m，注入压力下降39.6%。在微观可 视化模型中，纳米淀粉流体可以明显降低多孔介质中的含油饱和度，特别是多孔介质固体表面的油膜量明显 减少，提高驱油效果明显。在低渗透岩心中，纳米淀粉溶液的驱替前沿更加均匀，与水驱相比具有更大的波及体积。由于较大的波及体积、较高的驱油效率以及良好的润湿性等，注入0.4PV质量浓度为5000mg/L的纳米淀 粉流体后，低渗透岩心的采收率增幅达21百分点。研究结果可为低渗透油藏的提高采收率提供一种新的技术参考。

In order to further enhance the efficient application of nano oil displacement technology in low-permeability reservoirs，it is urgent to develop a new type of nano oil displacement products. As an environmentally friendly material，Nanostarch particles have a wide distribution in the world with the relatively low price，excellent performance，so that it has the potential to significantly improve oil recovery. In this paper，the process and mechanism of enhanced oil recovery of nano starch fluid were studied based on the basic physical properties of nano fluid，improving oil displacement effect，expanding the swept volume and other key indicators. by using the indoor static experiments，core displacement experiments，microscopic visualization experiments，CT scanning experiments，etc. The experimental results showed that，after the action of the nanostarch fluid with the concentration of 5000 mg/L and the size of 30 nm，the occurrence state of water molecules was changed. The phase transition temperature of water was increased from 102 ℃ to 110 ℃. The wetting contact angle of rock surface was reduced from 78 ° to 34.2 °，the oil-water interfacial tension was decreased from 20 mN/m to 0.56 mN/m，and the injection pressure was decreased by 39.6% . In the microscopic visualization model，nano starch fluid could significantly reduce the oil saturation，especially the amount of oil film on the solid surface of the porous media was significantly reduced，which could significantly improve the oil displacement effect. In low permeability cores，the displacement front of nanostarch solution was more uniform and had a higher sweep area than that of water flooding. Due to its large sweep volume，high oil displacement efficiency and good wettability，the nanostarch fluid could be used to enhance oil recovery in low-permeability porous media. After injection of 0.4 PV of nanostarch fluid with the concentration of 5000 mg/L，oil recovery was increased by up to 21 percentage point. The results of this study can provide a new technical approach for enhanced oil recovery in low permeability reservoirs.

10.19346/j.cnki.1000-4092.2024.01.010