摘要
为探究邯郸九龙矿构造煤在压力作用下对煤孔隙结构造成产生的影响,选取九龙矿瓦斯突出煤层-山西组2号碎粒煤及碎裂煤为研究对象,对煤样进行加压处理,并利用低温氮吸附仪对加压前后的煤样进行低温氮吸附实验。利用传统低温氮实验数据定性分析和分形理论定量分析的方法,对实验前后煤样孔隙发育规模和结构变化进行对比分析。实验结果显示:压力对煤中的孔隙结构会造成一定的影响,加压后的碎粒煤孔隙结构变化情况较小,碎裂煤孔隙结构变化较为明显。碎粒煤孔容贡献基本不发生变化,碎裂煤孔容贡献度会发生变化,且孔容贡献度占比会更倾向于更小的孔径,表明压力在对煤产生影响时,孔径小的孔径对压力反应比孔径大的孔径反应更明显。碎裂煤和碎粒煤比表面积贡献均为较小的孔径,基本在2~4 nm波动,比表面积孔径贡献范围有轻微后移,但幅度不大。碎粒煤和碎裂煤在加压前后,微孔的分形维数高,拟合度均为0.99以上,小孔和中孔的分形维数较高,拟合度均为0.94以上。加压后,碎粒煤的煤样微孔复杂情况具有更简单的趋势,中孔和小孔的复杂情况具有更复杂趋势,但趋势均不明显,而碎裂煤在微孔的孔隙情况有轻微的变简单,在中孔和小孔的孔隙情况有变复杂的趋势,且趋势较为明显。九龙矿2号碎裂煤储层改造可以考虑在本煤层或在顶底板围岩进行水力压裂,而碎粒煤则需要通过水力冲孔出煤卸压或在顶底板围岩进行水力压裂。
In order to explore the impact underground pressure on coal pore structure alteration of tectonic coal in Jiulong Mine,Handan,reptured coal and fragmented coal from the No.2 outburst coal seam of Shanxi Formation were selected as the research objects.The coal samples were pressurized by the tableting machine.Low-temperature nitrogen adsorption instrument was adopted to perform the adsorption tests on pressurized coal samples and unpressurized coal samples.Pore structural changes of pressurized coal samples and unpressurized coal samples were comparatively discussed and analyzed using the quantitative analysis method of fractal theory and qualitative analysis method of traditional low temperature nitrogen experimental data.The results show that pore structure alterations occurred under the influence of pressure and this impact is more influential for reptured coal samples compared with fragmented coal samples.The contribution of pore volume of fragmented coal didn t change basically.The contribution of pore volume of reptured coal would change,and the volume of micropores contributes more on the whole pore volumes which indicates that the radius of micropores is more likely to be affected than the mesopores and macropores under pressure.The specific surface area contribution of reptured coal and fragmented coal is smaller pores,basically fluctuating around 2~4 nm,and the contribution range of pore diameter has slightly shifted back,but the amplitude is not large.The fractal dimensions of micropores are the highest with the degree of fit of more than 0.99,followed by small pores and mesopores with the degree of fit of more than 0.94 after pressurization of reptured and fragmented coal samples.After pressurization,the complexity of micropores of fragmented coal samples becomes less complex while for small pores and mesopores,the pore structures become relatively more complex but this impact is not obvious.While for reptured coal samples,pore structures of micropores are less complex after pressurization and pore structures of small pores and mesopores become more complex.Hydraulic fracturing of coal seam or roof&floor is suggested to improve methane recovery of No.2 reptured coal seam of Jiulong coal mine,and for fragmented coal seams,hydraulic flushing the coal seams or hydraulic fracturing of roof and floor are suggested to improve seam permeability.
作者
张贝贝
沈军平
金超
刘剑
ZHANG Bei-bei;SHEN Jun-ping;JIN Chao;LIU Jian(School of Earth Science and Engineering,Hebei University of Engineering,Handan 056038,China;Key Laboratory of Coalbed Methane Resources&Reservoir Formation Process,Ministry of Education,China University of Mining and Technology,Xuzhou 221116,China;Aksu Industrial Vocational and Technical College,Aksu 842000,China)
出处
《科学技术与工程》
北大核心
2023年第35期14955-14963,共9页
Science Technology and Engineering
基金
河北省高等学校科学技术研究项目青年项目(QN2020430)
煤层气资源与成藏过程教育部重点实验室(中国矿业大学)开放研究基金(2019-005)
河北省重点研发计划(21374104D)。
关键词
九龙矿
孔隙结构
碎裂煤
碎粒煤
压力
Jiulong mine
pore structure
reptured coal
fragmented coal
pressure
