中文摘要：

基于压汞和核磁共振实验进行了致密岩心孔隙结构分类,提取了不同孔隙结构的铸体薄片并应用PSO多阈值分割算法得到孔隙-骨架二值图。结合孔隙结构的多重分形理论计算了不同孔隙结构的多重分形维数及多重分形谱,分析了多重分形维数与饱和中值压力、平均孔喉半径和核磁T2几何平均值的关系。研究表明：基于多重分维表征方法与压汞、核磁共振等实验具有一致性,不同孔隙结构岩石的多重分形特征各异,物性越差、孔隙结构越复杂,多重分形维数越大;多重分形维数与饱和中值压力成正比,与平均孔喉半径和核磁T2几何平均值成反比;D（min）与孔隙结构类型及其他孔隙结构表征参数的相关性最强,在缺乏压汞、核磁等实验数据时,基于铸体薄片的多重分形维数为致密岩石孔隙结构的定量表征提供了有利依据。

英文摘要：

The pore structure of tight cores is classified based on mercury injection and NMR core analysis,the cast slices of different pore structure are obtained, and two dimensional pore-matrix graphs of the cast slices are obtained by PSO multi-threshold segmentation algorithm. Multifractal dimension and multifractal spectrum of different types of pore structure are calculated based on the muhifractal theory of pore structure, and the relationships between multifractal dimension and median saturation pressure, average pore radius and nuclear magnetic T2 geometric mean. The results show that the pore structure characterization method based on muhi-fractal has the same effectiveness as mercury injection method and NMR core analysis method. The multi-fractal characteristics of different types of pore structure are different,and the worse the physical properties of cores,the more complex the pore structure,the greater the multifrac- tal dimension. It is also found that the multi-fractal dimension increases with the increase of median saturation pressure, and decreases with the increase of average pore radius and NMR T2 geometric mean. Dmin has the strongest correlation with pore structure type and other pore structure characterization parameters,in the absence of mercury penetration and NMR experimental data,the muhifractal dimension derived from cast slices can provide a favorable basis for the quantitative characterization of tight rock pore structure.