超临界CO_2作用后煤微观结构与渗透率变化规律实验研究  

Experimental Study of Coal Microstructure and Permeability Variation after of Supercritical CO_2 Penetration

作　　者：岳立新[1] 孙可明[2] YUE Li-xin SUN Ke-ming(College of Mechanical Engineering, Liaoning Technical University, Fuxin 123000, Liaoning, China School of Mechanics ＆ Engineering, Liaoning Technical University, Fuxin 123000, Liaoning, China)

机构地区：[1]辽宁工程技术大学机械学院,辽宁阜新123000 [2]辽宁工程技术大学力学与工程学院,辽宁阜新123000

出　　处：《实验力学》2017年第3期397-406,共10页Journal of Experimental Mechanics

基　　金：国家自然科学基金(51404135;51574137)资助

摘　　要：在宏观超临界CO_2增透实验基础上进行微观成像实验,提取煤微观孔隙特征,自编Matlab程序,计算孔隙率,得到煤各微区孔隙率和渗透率矩阵,绘制孔隙率和渗透率等值线图。结果表明:增透实验前后煤微观结构差别显著,经超临界CO_2作用后,煤微观孔隙充分发育,孔隙的数量、尺寸明显增加,孔隙率是增透前的9.11倍;随着孔隙压力的增大,煤中粒间孔隙数量增多,孔隙之间的连通性增加,孔隙率呈指数增大的趋势,煤体各微区孔隙率等值线密集程度增加;煤体的渗透率随着孔隙率的增加呈正指数递增的趋势,且随着孔隙压力的增加,渗透率呈指数递增的变化规律,渗透率等值线的密集程度增加,宏微观实验结果是一致的,随着注入超临界CO_2孔隙压力的增加,煤微观孔隙结构的发育程度提高,为煤层气的运移提供更多的通道,有效提高了煤体的渗透性。Microscopic imaging experiment was carried out on the basis of macroscopic supercritical CO2 penetration.Experiment includes extracting coal micro pore characteristics,compiling Matlab program to calculate porosity,obtaining matrix of porosity and permeability in coal each micro area,and finally drawing porosity and permeability contour plot.Results show：the microstructure of coal is significantly different before and after CO2 penetration.After CO2 penetration,micro pores of coal are fully developed;the number and size of pores increase obviousely;the porosity is 9.11 times higher than that before penetration.With the increase of pore pressure,the number of intergranular pores increases;the connectivity between pores increases;the porosity increases exponentially;the contour line density in micro regions of coal increases.The permeability of coal increases exponentially with the increase of porosity; with the increase of pore pressure,the permeability increases exponentially and permeability contour line density of permeability increases.The macroscopic and microscopic experimental results are consistent.With the increase of supercritical CO2 injection pore pressure,the development degree of coal micro pore structure is improved,which provides more channels for coal bed gas migration,effectively improves coal permeability.

关 键 词：超临界CO2 微观结构 渗透率 孔隙率 

分 类 号：P618.11[天文地球—矿床学]