摘要
为表征煤系沉积岩的孔隙结构与分形特征,选取中侏罗统页岩、泥岩和砂岩3种典型沉积岩进行了X射线衍射(XRD)分析、核磁共振(NMR)实验,运用分形理论讨论了NMR分形维数与矿物组成、物性参数之间的相互关系。结果表明:①基于弛豫时间截止值T2C,可将页岩、泥岩NMR分形维数划分为吸附孔隙分形维数DA(T2≤3 ms)和渗流孔隙分形维数DS(T2>3 ms)。②储层物性方面,NMR分形维数Df与孔隙率、渗透率、储层质量指数呈良好的线性负相关关系,说明NMR分形维数能够作为衡量岩石物性的重要指标。③矿物成分方面,石英、长石含量与分形维数Df呈弱负相关关系,黏土矿物由于受到沉积环境、理化性质和矿物本身含量等多因素作用,对分形维数的影响差异较为显著。
In order to characterize the pore structure and fractal characteristics of coal-measure sedimentary rocks,three types of typical sedimentary rocks of the Middle Jurassic shale,mudstone and sandstone were selected as the research objects.Through X-ray diffraction(XRD)analysis and nuclear magnetic resonance(NMR)experiment,the correlation between NMR fractal dimension,mineral composition and physical property parameters was discussed by using fractal theory.The results are as follows:①Based on the relaxation time cut-off value T2C,the NMR fractal dimension of shale and mudstone can be divided into the fractal dimension of adsorption pore DA(T2≤3 ms)and the fractal dimension of seepage pore DS(T2>3 ms).②In terms of reservoir physical properties,NMR fractal dimension Df has a good linear negative correlation with porosity,permeability,and reservoir quality in-dex, indicating that NMR fractal dimension can be used as an important indicator of rock physical properties. ③ In terms of mineral composition,the content of quartz and feldspar has a weak negative correlation with the fractal dimension Df,and clay minerals have different influences on the fractal di-mension due to multiple factors such as sedimentary environment,physical and chemical properties and mineral content.
作者
张娜
寻兴建
王帅栋
张浩宇
Zhang Na;Xun Xingjian;Wang Shuaidong;Zhang Haoyu(State Key Laboratory for GeoMechanics and Deep Underground Engineering,Beijing 100083,China;School of Mechanics and Civil Engineering,China University of Mining and Technology-Beijing,Beijing 100083,China)
出处
《矿业科学学报》
CSCD
2021年第5期623-632,共10页
Journal of Mining Science and Technology
基金
国家自然科学基金青年科学基金(41502264)
中央高校基本科研业务费专项基金(2020YJSSB07)
中国矿业大学(北京)大学生创新训练(C202006968)。
关键词
煤系沉积岩
孔隙结构
核磁共振
多重分形
渗透率
coal-measure sedimentary rocks
pore structure
nuclear magnetic resonance
multi-fractal dimension
permeability
