Two sets of Permo-Carboniferous and Jurassic coal -bearing strata have developed in the northern Ordos Basin .Probe into the diversity of two coal reservoirs can provide theoretical reference for CBM multi -layer drainage in the area ,and provide theoretical support for deep part and medium to low ranked coal CBM target optimization .The buried depth of Jurassic coal reservoir is shallower than that of Permo-Carboniferous coal reservoir, but thickness about the same;the coal macrolithotype of the former is mainly semi -dull to dull coal ,the later semibright to dull coal .Permo-Carboniferous coal reservoir porosity is 3.60%~7.40%, mainly micro-pores;specific surface area 10.24~14.22m 2/g;permeability (23.20~26.00) ×10 -3μm2.Jurassic coal reservoir porosity is gener-ally larger than 22%, individual samples near 30%;mean pore size is larger with contents of micropore , medium pore and large pore about the same;specific surface area 0.50~1.53m2/g;permeability (20.40~28.00) ×10 -3μm2.Compared to Permo-Carbonifer-ous coal reservoir , Jurassic coal reservoir has higher porosity , larger pore size , thus more favorable to CBM exploitation .Besides , the Langmuir volume of Permo -Carboniferous coal reservoir is 9.75~15.20 cm 3/g, average 11.47 cm 3/g;Jurassic coal reservoir 6.23~18.74 cm 3/g, average 11.99cm 3/g, about the same with the former.Overall, the two aged coal reservoirs all have good physical char -acteristics,while the Jurassic coal reservoir has better pore structure .%鄂尔多斯盆地北缘发育石炭-二叠纪和侏罗纪两套含煤岩系,探究两套煤储层特征的差异性,可以为该地区多套煤层共采提供理论参考,同时为深部煤层气和中低煤阶煤层气地质选区提供理论支撑.侏罗纪煤储层埋深较石炭-二叠纪煤储层浅,而厚度相当,前者以半暗-暗淡煤为主,后者以半亮-暗淡煤为主.研究区石炭-二叠纪煤储层孔隙度在3.60%~7.40%,以微孔为主,比表面积分布在10.24~14.22 m2/g;渗透率为(23.20~26.00)×10-3μm2;而侏罗纪煤储层孔隙度一般大于22%,个别样品孔隙度接近30%,平均孔径较大而微小孔、中孔和大孔含量大致相当,比表面积0.50~1.53 m 2/g,渗透率在(20.40~28.00)×10-3μm 2,相比于石炭-二叠纪煤储层,侏罗纪煤储层的孔隙度高、孔径大,对煤层气的开发更为有利.此外,研究区石炭-二叠纪煤储层兰氏体积分布在9.75~15.20 cm 3/g,平均11.47 cm 3/g;侏罗纪煤储层兰氏体积分布在6.23~18.74 cm 3/g,平均11.99 cm3/g,与石炭-二叠纪煤储层相当.因此,整体上看,石炭-二叠纪与侏罗纪煤储层均有良好的物性特征,而侏罗纪煤层拥有更好的孔隙结构.
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