文献类型：期刊文献

中文题名：CO_(2)相变致裂下煤体全孔径孔隙结构特征研究

英文题名：Full aperture pore structure characteristics of coal fractured by CO_(2)phase transition fracturing technology

作者：赵小英 江泽标 权西平 康向涛 陈思粮

第一作者：赵小英

机构：[1]贵州大学矿业学院,贵州贵阳550025;[2]贵州理工学院工程训练中心,贵州贵阳550032;[3]贵州省非金属矿产资源综合利用重点试验室,贵州贵阳550025

第一机构：贵州大学矿业学院,贵州贵阳550025

年份：2025

卷号：57

期号：12

起止页码：194-202

中文期刊名：煤炭工程

外文期刊名：Coal Engineering

收录：;北大核心:【北大核心2023】；

基金：国家自然科学基金地区基金(52064009);贵州省科技厅项目(黔科合支撑[2020]4Y050)。

语种：中文

中文关键词：CO_(2)相变致裂;分形特性;孔隙结构;渗透性;孔隙重构

外文关键词：CO_(2)phase transition fracturing technology;fractal characteristics;pore structure;permeability;pore reconstruction

摘要：为探究CO_(2)相变致裂对煤体全孔径孔隙结构的影响,在贵州六盘水大运及大河边煤矿采集CO_(2)致裂前后的煤样,通过高压压汞、低温N 2吸附与低压CO_(2)吸附实验,并结合分形理论分析孔隙结构特征与分形特性。结果表明:原煤孔隙主要为片状颗粒堆积形成的狭缝孔;经CO_(2)相变致裂后,微孔数量减少,中、大孔数量增多,孔隙结构重构,产生大量墨水瓶形的半开放型/开放型孔隙,促使微孔向中孔转化、中孔向大孔转化以及大孔进一步扩展。分形特性分析显示,CO_(2)相变致裂对不同尺度孔隙的影响存在差异:微孔分形维数增加,结构复杂性与非均质性增强;大孔分形维数降低,结构趋于简单且非均质性减弱;中孔在低压区(P/P_(0)≥0.5)的分形维数降低,结构简化且非均质性减弱,而高压区(P/P_(0)<0.5)的分形维数无明显变化规律。工程应用表明,CO_(2)相变致裂技术可显著降低瓦斯流量衰减系数,提高透气性系数与煤层渗透性,降低瓦斯含量,提升瓦斯抽采效率,为煤矿安全生产提供技术保障。
In order to investigate the effect of CO_(2)phase transition fracturing on the full aperture pore structure of the coal,coal samples before and after CO_(2)fracturing were selected from Liupanshui Danyun Coal Mine and Dahebian Coal Mine in Guizhou,China,and the pore characteristics and fractal properties of the coal body before and after fracturing were analyzed by mercury intrusion porosimetry,low-temperature N 2 adsorption test,low-pressure CO_(2)adsorption test,combining with the fractal theories.The results show that the pore structure of the original coal samples is mainly composed of slit pores formed by the accumulation of flake-shaped particles,and after the CO_(2)phase transition fracturing,the number of micropores in the coal decreases,while the number of mesopores and macropores increases,the pore structure develops,producing a large number of ink-bottle shaped semi-open/open pores,with the micropores developing into medium pores,the medium pores developing into large pores,and the large pores developing into larger pores.In terms of fractal characteristics,CO_(2)phase change fracturing has different effects on the structures of micropores,mesopores and macropores,with micropores increasing in fractal dimension,becoming more complex and non-homogeneous,macropores decreasing in fractal dimension,becoming simpler and less non-homogeneous,and mesopores in the low-pressure zone(P/P_(0)≥0.5)decreasing in fractal dimension,becoming simpler and less non-homogeneous.The fractal dimension of mesopores in the high-pressure region(P/P_(0)<0.5)does not show any obvious pattern.The results of engineering applications show that CO_(2)phase transition fracturing technology can significantly reduce the attenuation coefficient of gas flow,increase the permeability coefficient and permeability,reduce the gas content,and improve the efficiency of gas extraction.