致密油藏孔隙结构对纳米流体驱油效果的影响

Influence of Pore Structure of Tight Reservoir on Oil Displacement Effect of Nano Fluid

许康宁 丁彬 吴伟 耿向飞 华树常 陈明贵 石祺瑶

XU Kangning DING bin WUWei GEN xiangfei HUA Shuchang CHEN Minggui SHI Qiyao

吉林低渗-致密储层“孔小、喉更小”，原油储层流度低，导致水驱效果较差。采用一种核-壳结构的纳米流体 增渗驱油体系，通过岩心驱油实验评价纳米流体增渗驱油体系对致密岩心的驱油效率，通过岩心核磁共振测试 以及CT扫描重点研究致密油藏孔隙结构对纳米流体驱油效果的影响。研究结果表明：纳米流体增渗驱油体系 可降低致密岩心驱油实验的注入压力，最大降幅为46.2%；当致密储层孔隙结构较好时，驱油效果明显，最高提升 30.21%。纳米流体增渗驱油体系对分布在平均孔隙半径大于1 μm的原油驱油效果显著。岩心CT扫描研究发 现，致密岩心的平均孔喉半径、有效连通孔隙占比以及孔隙配位数均会对纳米流体增渗驱油体系注入压力及驱 油效率造成影响，其中平均孔喉半径和有效连通孔隙占比影响更大。

Due to small pores，smaller throat，and lower mobility of crude oil in Jilin low permeability tight reservoir，water drive effect is poor. A nano fluid enhanced permeability and oil displacement（NFEPOD）system was adopted，and through the core oil displacement experiment the oil displacement efficiency of the NFEPOD system on the tight core was investigated，through the core nuclear magnetic resonance test and CT scanning，the influence of the pore structure of the tight reservoir on the oil displacement effect of nano fluid was focused on. The results showed that the NFEPOD system could reduce the injection pressure of tight core oil displacement experiment，with a maximum decrease of 46.2%. When the pore structure of tight reservoir was good，the oil displacement effect was obvious，with a maximum increase of 30.21%. The NFEPOD system could remarkably enhanced oil recovery when the crude oil was distributed in pore throat with an average pore radius greater than 1 μm. CT scanning of cores showed that the average pore throat radius，effective connected pore ratio and pore coordination number of tight cores would affect the injection pressure and oil displacement efficiency of the NFEPOD system，the average pore throat radius and the proportion of effectively connected pores had a greater impact.

10.19346/j.cnki.1000-4092.2022.03.011