利用原子力显微镜表征页岩孔隙结构特征

页岩储层孔隙结构复杂,非均质性强,矿物组分多样,这些储层特性加大了页岩油的开采难度。为了更好的表征页岩孔隙结构,利用原子力显微镜（atomic force microscope,AFM)技术,结合Gwyddion软件对大港、吉木萨尔和松辽盆地页岩的孔隙结构以及表面粗糙度进行了表征。结合快速傅里叶转换分析页岩的非均质性,采用分水岭法识别孔隙分布特征,分析不同地区页岩储层的孔隙结构差异。原子力显微镜可以对页岩的表面形貌进行表征,通过平均粗糙度、均方粗糙度、表面偏度和峰度系数等参数对表面粗糙度进行评价,可以准确表征页岩纳米级的孔隙结构,包括孔隙数量、孔隙大小、孔隙面积、孔隙体积和孔隙度等。结果表明：大港和吉木萨尔页岩的表面高度较高,松辽盆地页岩表面高度较低,大港页岩非均质性较强,孔隙主要以微孔为主,吉木萨尔页岩和松辽盆地页岩非均质性较弱,中孔和宏孔数量较多,孔隙发育较好。

Characterization of pore structure of shale by atomic force microscopy

Shale reservoir has complex pore structure, strong heterogeneity and diverse mineral components, which make it more difficult to recover shale oil. In order to better characterize the pore structure of shale, atomic force microscopy and Gwyddion software were used to characterize the pore structure and surface roughness of dagang, Jimusar and Songliao basins shales. Fast Fourier transform was used to analyze the heterogeneity of shale, watershed method was used to identify the pore distribution characteristics, and the pore structure differences of shale reservoirs in different areas were analyzed. Atomic force microscope can characterizing the surface morphology of shale, by an average of roughness, the mean square, surface roughness of skewness and kurtosis coefficient to evaluate surface roughness parameters, such as, can accurate characterization of nanoscale pore structure of shale, including pore volume, pore size and pore size, pore volume and porosity, etc. The results show that dagang and Jimsar shales have higher surface heights, while Songliao basins shales have lower surface heights. Dagang shales have stronger heterogeneity, and the pores are mainly micropores, while Jimsar shales and Songliao basins shales have weaker heterogeneity, and there are more mesopores and macropores, and the pores are well developed.