清洁压裂液作用前后煤孔隙结构及分形特征研究  

Study on the pore structure and fractal characteristics of coalbefore and after the action of clean fracturing fluid

作　　者：王昌伟 左少杰 彭首清 许治远 甘瑞 Wang Changwei;Zuo Shaojie;Peng Shouqing;Xu Zhiyuan;Gan Rui(College of Mining Engineering,Guizhou University,Guiyang Guizhou 550025,China;Institute of Gas Disaster Prevention and Coalbed Methane Development,Guizhou University,Guiyang Guizhou 550025,China)

机构地区：[1]贵州大学矿业学院,贵州贵阳550025 [2]贵州大学瓦斯灾害防治与煤层气开发研究所,贵州贵阳550025

出　　处：《化工矿物与加工》2024年第2期34-39,共6页Industrial Minerals & Processing

基　　金：贵州省省级科技计划项目(黔科合基础-ZK[2022]一般163);贵州大学引进人才科研项目(贵大人基合字〔2020〕57号)。

摘　　要：煤孔隙结构特征及分形特征是揭示瓦斯在煤体中的赋存机理及解吸运移规律的重要手段。以沈阳某煤矿的煤样为研究对象进行了清洁压裂液浸泡试验,分别采用扫描电子显微镜、孔隙-裂隙分析系统、氮气吸附和煤表面分形特征对煤表面的孔隙结构进行表征,对清洁压裂液处理前后煤孔隙结构的变化进行了对比分析,结果表明:经清洁压裂液处理后,煤样的孔隙结构得到了较好的发育,煤样表面孔隙数量约为原煤的2.9倍、平均面积约为原煤的2.66倍、平均周长增加了23.06%、平均形状因子增加了30.91%;煤样氮气吸附量从1.5036 mL/g增至2.8255 mL/g,增加的孔隙半径小于10 nm,孔隙连通性增强;清洁压裂液能使吸附孔分形维数增大、渗流孔分形维数减小,煤样内部结构更加简单,孔隙之间的连通性增强,其中吸附孔分形维数从2.331增至2.845,增幅为22.05%;渗流孔分形维数从2.865减至1.756,减幅为38.71%。孔隙结构的定量表征结果显示,清洁压裂液对煤孔隙的发育有一定的促进作用。The characteristics of coal pore structure and fractal characteristics are important means to reveal the occurrence mechanism and desorption migration law of gas in coal.The soaking experiment of clean fracturing fluid was conducted on coal samples from a coal mine in Shenyang.The pore structure of the coal surface was characterized by scanning electron microscopy,pore-fracture analysis system,nitrogen adsorption,and coal surface fractal characteristics to compare and analyze the changes of coal pore structure before and after clean fracturing fluid treatment.The results showed that after treatment with clean fracturing fluid,the pore structure of the coal samples was well developed.The number of pores on the surface of the coal samples is about 2.9 times that of the raw coal,the average area is about 2.66 times that of the raw coal,the average circumference has increased by 23.06%,and the average shape factor has increased by 30.91%;The nitrogen adsorption capacity of coal samples increased from 1.5036 mL/g to 2.8255 mL/g,with increased pore radius of less than 10 nm and enhanced pore connectivity;Clean fracturing fluid can increase the fractal dimension of adsorption pores and decrease the fractal dimension of seepage pores,simplify the internal structure of coal samples,and enhance the connectivity between pores.The fractal dimension of adsorption pores increased from 2.331 to 2.845,and an increase rate of 22.05%;The fractal dimension of seepage pores decreased from 2.865 to 1.756,with the reduction rate 38.71%.The results quantitative characterization in pore structure show that clean fracturing fluid has certain promoting effect on the development of coal pores.

关 键 词：清洁压裂液 孔隙结构 电镜扫描 氮气吸附 孔隙-裂隙分析系统 分形维数 

分 类 号：TD712[矿业工程—矿井通风与安全]