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分形维数是多孔介质不规则程度的度量。对川南下志留统龙马溪组页岩的氮气吸附法测量结果分析，采用基于 FHH 模型的分形维数计算模型，得到龙马溪组页岩孔隙的分形维数。川南龙马溪组页岩具有明显的分形特征及较大的分形维数，分形维数变化范围在2．6005～2．648，平均为2．6252。页岩分形维数与页岩比表面积和孔容呈正相关，且页岩中的微孔对页岩分形维数有重要影响。有机质、石英和黏土矿物对页岩分形维数影响较大，长石和碳酸盐对页岩分形维数影响较小；页岩分形维数与有机碳含量和石英含量呈正相关，而与黏土矿物含量呈负相关，其中黏土矿物中伊利石和绿泥石对页岩孔隙结构影响不同。页岩分形维数越大，页岩孔隙结构越复杂或孔隙表面越粗糙，页岩的吸附气体能力越强，但页岩气的解吸、扩散及渗流变得越困难。

The fractal dimension is a measure of the degree of irregular porous media.This paper calculates the fractal dimensions of the pore structure of the Lower Silurian Longmaxi Formation shale in the south of Sichuan Basin by using the fractal dimension computational model based on FHH model and analyzes the measured results of the pore structure by the nitrogen adsorption method.The result shows that the pore structure of Longmaxi Formation shale has typical fractal nature,the fractal dimensions of pore structures of the Longmaxi Formation shale are relatively big and the value of the fractal dimension is 2.3559~2.6577,with an average of 2.488.There is a positive correlation between the fractal dimension of the shale and the specific surface area,the pore volume.Especially, the micropores in the shale have a significant impact on the fractal dimension.The organic matter, quartz and clay minerals have an important influence on the fractal dimension,whereas the feldspars and carbonates have a little influence on the fractal dimension.The fractal dimensions have positive
relationships with the contents of total organic carbon and quartz,whereas there is a negative correlation between the fractal dimension and clay minerals contents,and the illite and chlorite have a different impact on the shale pore structure.The shale with a higher fractal dimension has a more complicated pore structure and a more irregular pore surface,and a higher adsorption capacity of the shale.However,the shale with a higher fractal dimension has lower capacity of desorption,diffusion and seepage of the shale gas.