纳米级孔隙油水两相渗流规律及相对渗透率计算方法  

The Law of Oil-water Two-phase Seepage and the CalculationMethod of Relative Permeability in Nanoscale Pores

作　　者：庄春辉 李亚军[1] 张欢 桑茜 宫厚健[1] 徐龙[1] 董明哲[1] ZHUANG Chun-hui;LI Ya-jun;ZHANG Huan;SANG Qian;GONG Hou-jian;XU Long;DONG Ming-zhe(School of Petroleum Engineering,China University of Petroleum(East China),Qingdao 266580,China)

机构地区：[1]中国石油大学(华东)石油工程学院,青岛266580

出　　处：《科学技术与工程》2025年第11期4505-4514,共10页Science Technology and Engineering

基　　金：国家自然科学基金(42090024)。

摘　　要：页岩、致密砂岩等非常规油气储层中发育有微纳米孔隙,微纳米孔隙中油水两相渗流规律和相对渗透率研究是这类储层有效开发的理论基础。针对纳米孔隙中的油水两相流动问题,基于Hagen-Poiseuille(HP)方程,考虑油水分布、黏性耦合、多层吸附、滑移等微观渗流机理,建立了纳米级孔隙油水两相渗流的数学模型,在此基础上形成了相对渗透率的计算方法,通过拟合LBM(Lattice Boltzmann method)计算结果验证了模型的正确性,通过参数敏感性分析,研究了纳米孔隙中油水两相渗流特征和相对渗透率影响规律。研究结果表明:滑移长度对油水速度分布有较大影响;润湿接触角的增加导致油水相对渗透率均有不同程度的增加;随着黏度比增加,油相相对渗透率显著增加,水相相对渗透率没有明显变化;由于正滑移的存在,会出现相对渗透率大于1的情况;随孔隙半径的增大,流体流动的孔隙面积增加,因此油水两相相对渗透率均增加。研究对阐明微观多孔介质流体流动机制和页岩油的开采具有一定的指导意义。Micro-nano pores are developed in unconventional oil and gas reservoirs such as shale and tight sandstone,and the study of oil-water two-phase seepage law and relative permeability in micro-nano pores is the theoretical basis for the effective development of such reservoirs.Addressing the two-phase flow of oil and water within nanopores,a mathematical model was established for nanopore-scale two-phase oil-water flow,grounded on the Hagen-Poiseuille(HP)equation and taking into account microscale seepage mechanisms such as oil-water distribution,viscous coupling,multi-layer adsorption,and slippage.Based on this model,a calculation method for relative permeability was developed.The validity of the model was verified by fitting the results from Lattice Boltzmann method(LBM)simulations.Furthermore,through a parametric sensitivity analysis,the characteristics of two-phase oil-water flow and the influence patterns of relative permeability within nanopores were investigated.The results showed that the slip length significantly impacted the velocity distribution of oil and water.An increase in the wetting contact angle led to varying degrees of augmentation in both oil and water relative permeabilities.As the viscosity ratio rose,the oil-phase relative permeability experienced a notable increase,while the water-phase relative permeability remained relatively unchanged.The presence of positive slip could result in relative permeabilities exceeding unity.As the pore radius enlarged,the pore area available for fluid flow expanded,thereby enhancing both oil and water relative permeabilities.This study holds guiding significance for elucidating the fluid flow mechanisms in micro-porous media and facilitating the exploitation of shale oil.

关 键 词：页岩油 纳米级孔隙 相对渗透率 滑移长度 润湿性 

分 类 号：TE343[石油与天然气工程—油气田开发工程]