论文部分内容阅读
为研究海陆过渡相页岩的孔隙结构及分形特征,对采自沁水盆地的12块样品进行了低温氮气吸附、扫描电镜、X-射线衍射和有机质含量等系列分析测试。结果表明,研究区页岩黏土矿物最为富集,石英含量次之,有机质含量平均为2.98%,干酪根类型以Ⅲ型为主。中孔是研究区页岩的主体孔隙,对孔隙体积和比表面积贡献最大。研究区页岩孔隙具有明显的分形特征,利用FHH模型计算得到2种分形维数(D1、D2)。黏土矿物含量与D1、D2具有较好的正相关性,有机质含量与分形维数无明显相关关系。D1和D2具有一定的正相关性,可以共同定量表征页岩孔隙结构的复杂程度和孔隙表面的粗糙程度。分形维数D1、D2越大,页岩孔隙体积和比表面积越大,越有利于气体的富集,但是D2越大孔隙结构越趋于复杂,不利于气体的渗流。分形维数D1越大而D2适中的页岩储集能力较强,且有利于页岩气的开发。
In order to study the pore structure and fractal characteristics of marine-continental transitional shales, 12 samples collected from Qinshui Basin were analyzed by low-temperature nitrogen adsorption, scanning electron microscopy, X-ray diffraction and organic matter content analysis. The results show that shale clay minerals are the most abundant in the study area, followed by quartz with an average of 2.98% organic matter and type Ⅲ of kerogen. The mesopores are the main pores of the shale in the study area and contribute the most to the pore volume and specific surface area. The shale porosity in the study area has obvious fractal characteristics. Two fractal dimensions (D1, D2) are calculated by FHH model. There is a good positive correlation between clay mineral content and D1 and D2. There is no significant correlation between the content of organic matter and the fractal dimension. D1 and D2 have a certain positive correlation, which can be used to quantitatively characterize the complexity of the pore structure and the roughness of the pore surface. The larger the fractal dimension D1 and D2 are, the larger the shale pore volume and specific surface area are, the more conducive to gas enrichment. However, the larger the D2 is, the more complicated the pore structure is, which is not conducive to gas seepage. The larger the fractal dimension D1 and the more moderate D2 have stronger shale reservoir capacity, which is beneficial to the development of shale gas.