摘要
非常规油气开采、地热开采过程中,复杂孔隙岩石的两相驱替流动特性直接影响其采收率,因此其过程研究备受关注。以4类有序、无序孔隙结构介质为研究对象,自主搭建了微流体试验可视化装置,开展5种流量及4种被驱替流体黏度在介质中的流动特性试验研究,深入分析毛细管数、黏度比及孔隙结构无序性对两相驱替过程的影响规律。结果表明:入侵相分形维数与驱替模式有关,与驱替效率呈正相关,且分形维数是入侵相含量的普适函数。驱替结束时的分布特征与驱替模式密切相关:稳定驱替向毛细指进转变,伴随着被捕获相数量和标准差的增大。毛细指进向黏性指进转变与毛细指进向规则指进的转变相同,伴随着被捕获相数量的减小和标准差的增大。考虑流体黏度比的影响,建立了修正毛细管数与入侵相驱替饱和度的关系式,可预测考虑黏度比影响的驱替效率。
The two-phase displacement flow characteristics within complex porous rocks are pivotal to the recovery rates in unconventional oil and gas recovery as well as geothermal exploitation,garnering significant research interest.This study focuses on four types of porous media with both ordered and disordered structures,employing a self-constructed microfluidic experimental visualization setup to investigate the flow characteristics under five different flow rates and four distinct viscosities of the displaced fluid.The influence of capillary number,viscosity ratio,and the disorder of the porous structure on the two-phase displacement process is thoroughly analyzed.Findings indicate that the fractal dimension of the invading phase is correlated with the displacement pattern and positively associated with displacement efficiency,serving as a universal function of the invading phase's content.The distribution characteristics at displacement completion are intimately linked to the displacement mode.A transition from compact displacement to capillary fingering is marked by an increase in the quantity and standard deviation of the trapped phase.Conversely,the shift from capillary fingering to viscous fingering mirrors the transition from capillary fingering to ordered dendritic,characterized by a reduction in trapped phase quantity and an enlargement of standard deviation.Incorporating the impact of fluid viscosity ratios,a modified relationship between the capillary number and the displacement saturation of the invading phase is formulated,enabling the prediction of displacement efficiency that accounts for viscosity ratio effects.
作者
刘先珊
孙梦
郑志伟
熊振瑀
于明智
曹伊婷
宋昱霖
黄子宣
LIU Xian-shan;SUN Meng;ZHENG Zhi-wei;XIONG Zhen-yu;YU Ming-zhi;CAO Yi-ting;SONG Yu-lin;HUANG Zi-xuan(School of Civil Engineering,Chongqing University,Chongqing 400045,China;Key Laboratory of New Technology for Construction of Cities in Mountain Area of the Ministry of Education,Chongqing University,Chongqing 400045,China)
出处
《岩土力学》
北大核心
2025年第8期2363-2375,共13页
Rock and Soil Mechanics
基金
国家自然科学基金(No.52279094,No.52478328)
重庆市自然科学基金(No.CSTB2023NSCQ-MSX0069)。
关键词
复杂孔隙
结构无序性
毛细管数
黏度比
驱替效率
complex pores
structural disorder
capillary number
viscosity ratio
displacement efficiency
