Abstract:

It is too expensive and has more time consuming by using X-ray computerized tomography (CT) to obtain the real 3D digital cores for representing the true microstructures of rocks.It is important to reconstruct 3D digital cores based on 2D images of rocks and evaluate the accuracy of reconstructed digital cores.The 3D digital cores were reconstructed using sequence indicator simulation on the basis of 2D images of rocks.The pore size distribution function,local porosity distribution function and average percolation probability function were calculated in the real 3D digital cores and the reconstructed digital cores.The bulk modulus and formation factors of those 3D digital cores were simulated by finite element method.The comparison of the parameters obtained from the reconstructed digital core with those from the true digital core indicates that the reconstructed digital core is similar to the true digital core in porosity,variogram function and homogeneity.The reconstructed digital core has smaller average pore size and worse connectivity than the true one.

Key words: 3D digital core, sequence indicator simulation, local porosity theory, bulk modulus, formation factor, finite element method

摘要：

采用X射线CT获得反映岩石微观结构的三维真实数字岩心过于昂贵和费时,因此正确评价利用岩心二维图像重建三维数字岩心的准确性具有重要的应用价值。利用顺序指示模拟方法,依据岩心的二维图像重建三维数字岩心,并计算了真实数字岩心与重建数字岩心的孔隙尺寸分布函数、局部孔隙度分布函数和平均渗流概率函数。应用有限元方法计算了重建数字岩心与真实数字岩心的体积模量和地层因素。重建数字岩心与真实数字岩心的对比表明,两者具有相同的孔隙度、变差函数和均质性,但相比真实数字岩心,重建数字岩心的平均孔隙半径偏小,孔隙连通性较差。

关键词: 三维数字岩心, 顺序指示模拟, 局部孔隙度理论, 体积模量, 地层因素, 有限元方法