Abstract:

The porosity distributions at different section of thirteen sandstone cores were studied by using the X-ray CT scanning system. The 3-D distributions of the core porosity were determined with the 3-D reconstruction technique. The porosity distributions and heterogeneity of those cores were observed clearly in the level of "pore group". The observed porosities at different section were analyzed and characterized quantitatively with the statistics method. Three scanned cores were taken as the example to show the porosity distributions. The obvious stratification phenomena exist in the S138 core, and the heterogeneity is serious. The standard deviation and nonuniform coefficient are great. The porosity distribution is uneven, and the pore sorting is bad. There are more low-porosity areas and less high-porosity areas in each section of the No.71 core, and the average porosity of the core is lower. There are more high-porosity areas and local low-porosity areas at each section of the S35 core. The average porosity of this core is high, and the core is homogenous. The standard deviation and nonuniform coefficient are lowest, and the pore distribution is uniform. The pore sorting of this core is good.

Key words: X-ray CT, sandstone core, pore characteristics, heterogeneity, quantitative analysis

摘要：

应用CT扫描系统对13个岩心连续进行扫描,并应用三维重建技术得到岩心的三维孔隙变化,在"孔群级"尺度上清楚地观察到岩心内部的孔隙变化和非均质特征。应用统计学方法,对不同截面上测量的孔隙度进行定量分析与表征。S138号岩心存在着明显的层理现象,非均质性严重,岩心孔隙度的标准偏差和不均匀系数较高,孔隙分布不均匀,分选性差。71号岩心截面内低孔隙区较多,高孔隙区较少,岩心的平均孔隙度较低。S35号岩心的平均孔隙度高,岩心比较均质,岩心孔隙度的标准偏差与不均匀系数最小,孔隙分布均匀,分选性好。

关键词: CT技术, 砂岩岩心, 孔隙特征, 非均质性, 定量分析