过程模拟法重建三维数字岩芯的准确性评价

Accuracy Evaluation on 3D Digital Cores Reconstruction by Process-based Method

由于利用X射线CT扫描获得反映真实岩石微观结构的三维数字岩芯过于昂贵和费时,因此,正确评价利用岩芯二维薄片图像重建三维数字岩芯的准确性具有重要理论和应用价值。采用过程模拟法,依据岩芯的二维薄片图像,通过模拟真实岩石的形成过程——沉积过程,压实过程和成岩作用重建了三维数字岩芯,并且应用局部孔隙度分布函数和平均渗流概率函数进行了重建三维数字岩芯的准确性评价。结果表明:过程模拟法重建的三维数字岩芯与真实岩芯具有相同的均匀性和连通性,且重建三维数字岩芯与真实数字岩芯都是各向同性的。重建的三维数字岩芯不仅可以用来表征真实岩芯的孔隙结构,而且也可以作为其他岩石物理属性模拟的基础。

It is too expensive and time consuming by use X-ray computerized tomography（CT） to obtain the real 3D digital cores for representing the true microstructures of rocks. It is important in both theory and applications to reconstruct 3D digital cores based on 2D thin section of rocks and evaluate the accuracy of reconstructed digital cores. 3D digital core was reconstructed utilizing petrographical information obtained from two dimensional thin sections to model the results of the main sedimentary rocks forming processes-sedimentation, compaction, and diagenesis. The accuracy of this method is evaluated by calculating local porosity distribution fimction and average percolation probability function in real 3D digital cores and the reconstructed digital cores. The results show that the homogeneity and connectivity of reconstructed three-dimension digital core by process-based method are similar to those of true 3D digital core and both of the reconstructed 3D digital core and true 3D digital core are !sotropic. Reconstruction of 3D digital cores can be used to characterize the pore structure of the true core, and can also be used as the basis for simulation of other physical properties.