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1、煤的孔隙综合分形维数研究刘高峰,张子戌(河南理工大学资源环境学院,河河南省瓦斯地质与瓦斯治理重点实验室一省部共建国家重点实验室培育基地,河南焦作454000)摘要:选择北皂矿褐煤、蔡园矿气煤、西曲矿焦煤和古汉山矿无烟煤作为研究対象,采用压汞法和低温液氮吸附法分析煤的孔隙结构以及孔隙形态,计算了煤小不同孔径段的分形维数。压汞法计算结果显示,褐煤、气煤与焦煤孔径大于或等于10nm的孔径段具有明显的分形特征,孔径小T10nm的孔径段不具有分形特征;而无烟煤孔径大丁•或等TlOOnm的孔径段具有明显的分形
2、特征,孔径小于lOOnm的孔径段不具冇分形特征。液氮吸附法计算结果显示,孔径范围2.03〜361.14nm的煤孔隙分形特征明显,英屮以孔径10nm和lOOnm为界的分形维数有所不同。基与此,定义并计算了煤的孔隙综合分形维数,实现了煤孔隙全孔径分形维数的统一,使于对煤孔隙结构非均质性进行整体表征。关键词:煤;孔隙;压汞法;液氮吸附法;分形维数屮图分类号:P61&11ComprehensivefractaldimensionofcoalporosityLIUGaofeng,ZHANGZixu(Stat
3、eKeyLaboratoryCultivationBaseforGasGeologyandGasControl,InstituteofResourcesandEnvironment,HenanPolytechnicUniversity,Jiaozuo,Henan454000)Abstract:Mercuryintrusionporosimetryandnitrogenadsoiptionexperimentwereaplliedtoanalyzetheporestructureandmorphol
4、ogyofthebrown,gas,cokingandanthracitecoalsamplesrespectivelycollectedfromtheBeozhao,Caiyuan,XiquandGuhanshanmines.AndthefractaldimensionsofcoalsamplesdifferentporesizeswerecalculatedbytheMercuryintrusionporosimetryandNitrogenadsorptionexperimentaldata
5、・ThecoalfractaldimensionresultsinMercuryintrusionporosimetryshowthatthebrown,gas,cokingcoalporefractalcharacteristicsisconspicuouswhentheapertureisgreaterthanorequaltolOnmanditislessthan1OOnmabouttheanthracitecoal,whileitisnotobviouswhentheapertureisl
6、essthanlOnmandlOOnm.AndThecoalfractaldimensionresultsinNitrogenadsorptionshowthatthecoalporefractalcharacteristicsisconspicuouswhentheapertureisgreaterthanorequalto2.03nmandlessthanorequalto361」4nm,butthefractaldimensionsofcoalsamplesaredifferentwith1
7、OnmandlOOnmthreshold.Onthebasisoftheabovestudy,thecoalporositycomprehensivefractaldimensionwasdefinedandcalculated・Throughthisstudy,thefractaldimensionsofthecoalporefullaperturehavebeenunifiedeffectivelyandthecoalporefractalresearchhasbeenimproved.Soi
8、tisconvenienttothecharacterizationofthenon-unifbrmityofcoal.Keywords:coal;pore;mercuryintrusion;nitrogenadsorption;fractaldimension0引言煤储层是一种双孔隙岩层,由基质孔隙和裂隙组成,煤的孔径结构是研究煤层气赋存状态、气水介质与煤基质块间物理、化学作用以及煤层气解吸、扩散和渗流的基础[同。煤具冇表面和结构的非均质性,主要表现为煤农面的不均匀,以及煤结构具