高活性纳米流体的原位流度控制及驱油效率研究

Research on in-situ mobility control and oil displacement efficiency of highly active nanofluid

由于纳米流体的界面效应、小尺度特征,在提高采收率领域具有较大应用潜力,但其驱油机理尚待进一步明确。为了进一步研究纳米流体的驱油机理和驱油效率,采用硅基纳米球与表面活性剂耦合的方式研发高活性纳米流体,借助静态宏-介-微观实验和岩心物理模拟,阐明高活性纳米流体形成乳状液的流度控制和介观驱油效率。实验结果表明,高活性纳米流体可降低普通稠油界面张力至10^(-2) mN·m^(-1)数量级,在油藏含水率饱和度30~80%条件,高活性纳米流体干预的油水乳化液粘度是原油粘度的1.28~4.32倍,表现良好原位流度控制性能;高活性纳米流体与岩心渗透率适应性强,水驱至含水率98%,0.6倍孔隙体积的0.4wt%高活性纳米流体通过原位流度控制,显著提高采收率达25%以上。研究结果深化了纳米流体驱油机理,同时为纳米驱提高采收率提供新路径。

Due to the interfacial effect and small-scale characteristics of nanofluids,they have great application potential in the field of enhanced oil recovery,but their oil displacement mechanism needs to be further clarified.In order to further study the oil displacement mechanism and oil displacement efficiency of nanofluids,a highly active nanofluid was developed by coupling silicon-based nanospheres and surfactants.With the help of static macro-medium-micro experiments and core physical simulations,the highly active nanofluids were clarified in-situ mobility control and mesoscopic oil displacement efficiency by in-situ producing emulsions.The experimental results show that the high activity nanofluid can reduce the interfacial tension of ordinary heavy oil to the order of 10^(-2) mN·m^(-1).Meanwhile,the viscosity of these induced emulsions are 1.28-4.32 times the viscosity of crude oil at a wide range of water saturations from 30%to 80%,suggesting a good in-situ mobility control performance of the this highly active nanofluid.Moreover,high activity nanofluid has strong adaptability to core permeability,when the water cut reaches 98%,0.6 pore volume of highly active nanofluid with mass concentration of 0.4%tunes the mobility by in-situ inducing the emulsion,and more than 25%of crude oil is significantly recovered.The results deepen the mechanism of nanofluid flooding,and at the same time provide a new path for nanofluid flooding to improve oil recovery.