基于氮气吸附和压汞定量表征砂岩吸水孔隙结构演化规律
Quantitative characterization of water absorption pore structure evolution in sandstone based on nitrogen adsorption and mercury intrusion
孙晓明 1丁佳旭 1何林森 1石富坤 1缪澄宇 1张勇 1朱明群 1杨金坤 1谢铖1
作者信息
- 1. State Key Laboratory for Geomechanics Deep Underground Engineering,China University of Mining and Technology-Beijing,Beijing 100083,China;School of Mechanics and Civil Engineering,China University of Mining and Technology-Beijing,Beijing 100083,China
- 折叠
摘要
为了探究水对岩石孔隙结构的作用机制,本文依托山东万福煤矿砂岩地层,针对不同浸泡时间作用下的砂岩试样,开展扫描电镜、氮气吸脱附和高压压汞联合孔隙结构测试实验,分析微孔(<2 nm)、介孔(2～50 nm)和大孔(>50 nm)的孔隙结构变化规律.结果表明:砂岩孔隙结构类型为狭窄型和楔形结构,孔隙之间具有连通成缝的能力.砂岩吸水过程中孔隙度先减少后增加.微孔占比先减少后增加,介孔和大孔占比先增加后减少.根据广义分形维数和谱宽定量评估孔隙结构,得出其与孔隙质量正相关,即分维差值和谱宽越大,孔隙结构越复杂;而与岩石孔隙度呈负相关,即较大孔隙度对应较小的分维数差值和谱宽.
Abstract
To investigate the mechanism of water's effect on the pore structure of rocks,this study relies on the sandstone formation in Wanfu Coal Mine,Shandong,China.Scanning electron microscopy(SEM),nitrogen adsorption-desorption,and high-pressure mercury intrusion combined with pore structure testing experiments were conducted on sandstone samples subjected to different immersion times.The aim was to analyze the variations in the pore structure of micropores(<2 nm),mesopores(2-50 nm),and macropores(>50 nm).The results indicate that the pore structure of the sandstone consists mainly of narrow and wedge-shaped structures.The pores have the ability to connect and form fissures.During the water absorption process,the porosity of the sandstone initially decreases and then increases.The proportion of micropores decreases initially and then increases,while the proportion of mesopores and macropores increases initially and then decreases.According to the quantitative assessment of pore structure using generalized fractal dimension and spectral width,it is found that there is a positive correlation between pore structure and pore quality.That is,as the difference in fractal dimension and spectral width increases,the pore structure becomes more complex.There is a negative correlation between pore structure and porosity,that is,larger porosity corresponds to smaller differences in fractal dimension and spectral width.
关键词
水岩作用/砂岩/孔隙结构/联合表征/多重分形Key words
water-rock interaction/sandstone/pore structure/joint representation/multifractal引用本文复制引用
基金项目
National Natural Science Foundation of China(52174096)
Special Fund of Basic Research and Operating of China University of Mining&Technology-Beijing(2022YJSSB03)
出版年
2024
NETL
NSTL
万方数据