基于AFM表征的页岩孔隙特征及其与解析气量关系

页岩储层的孔隙结构影响着页岩气的储集特性。为了较为真实地反映样品表面孔隙三维结构，著者选用原子力显微镜研究页岩微-纳米孔隙特征。以重庆市涪陵地区焦页1井（JY1）和渝参4井（YC4）典型样品为研究对象，用原子力显微镜表征岩样的微观结构，获取岩样的三维形貌图，分析岩样的孔隙分布特征和储集空间特征，构建代表岩样孔隙特征的参数。分别比较相同井号不同井段之间的特征参数差异和不同井号之间的特征参数差异，从而定量描述岩样的形貌特征。结合样品提取现场解析气量数据，建立JY1、YC4样品的解析气量与特征参数之间的关系。结果表明：JY1样品的储集空间密集，孔隙占的空间相对多，其微观结构更有利于气体的吸附和储集；结合两口井取心现场解析页岩气量分析发现，JY1、YC4样品的空间起伏度FDI与现场解析气量均呈现正相关关系。

AFM Based Pore Characterization of Shales and Its Relation to the Analytical Gas

The pore structure of shale reservoirs has a very significant impact on shale gas reservoir. An atomic force microscope (AFM) has unique advantage in characterization of micro-nanoscale structure, and can reflect three-dimensional structure of the surface of a sample. For the study of the relationship between micro-nanometer pore characterization of shales and the amount of field analytical gas extracted from core, we choose typical samples of Jiaoye 1 well (JY1) and Yucan 4 well (YC4) from Fuling of Chongqing as research objects. We get the micro-structure characterization of the rock samples by atomic force microscope, by obtaining three-dimensional topographies of the samples, and by analyzing the features of pore distribution and reservoir space of the samples. We then build parameters that represent internal characteristics of rock samples. Having compared the differences of the characteristic parameters from different well sections in the same well, and the differences of characteristic parameters from different wells respectively, we describe the morphology features of the rock samples quantitatively. Combined with the data of field analytical gas, we build the relationship between the amount of field analytical gas and characteristic parameters of JY1 and YC4 samples, respectively. The results show that relative to the YC4 samples, JY1 samples show more intensive reservoir spacesis, and higher porosity, and more beneficial to the storage of gas. The results also show that there is a positive correlation between the fluctuation degree of interspace and the amount of the field analytical gas of JY1 and YC4 samples. Our results may have significance for the quantitative evaluation of the relation between exploitable volume and the micro-pore structure of shale gas.