An image-based effective medium approximation (EMA) is developed so as to permit very fast transport properties evaluations of 3D porous media. From an image-based porous network (IBPN) built upon digital image processing of 3D binary images, we focus on throat’s local geometrical properties at the pore scale, for being the most sensible structural units which build up the local pressure. This approach is a 3D image–based extension of the critical point approach proposed in 2D fractures. We show, from analyzing various core rock samples available in the literature, that the asymptotic assumptions associated with the preeminence of critical points in throats are indeed geometrically relevant. We then describe how the image-based EMA evaluated from the conductances computed from the discrete IBPN can be reliably evaluated. The proposed method is evaluated upon the estimation of core sample permeability from binarized image obtained using X-ray tomography. Since it combines digital image treatments with statistical data post-processing without the need of computational fluid dynamics (CFD) computation, it is extremely cost efficient. The results are compared with a micro-scale Stokes flow computation in various rock samples. The sensitivity to the pore discretization also is discussed and illustrated.

开发了基于图像的有效介质近似（EMA），以便能够非常快速地评估3D多孔介质的传输性能。通过基于对3D二值图像进行数字图像处理的基于图像的多孔网络（IBPN），我们将注意力集中在孔尺度上的喉咙局部几何特性，因为它们是建立局部压力的最明智的结构单元。这种方法是对2D裂缝中提出的临界点方法的3D图像扩展。通过分析文献中提供的各种岩心样本，我们表明，与喉咙中的临界点占优相关的渐近假设确实在几何上是相关的。然后，我们描述如何可靠地评估从离散IBPN计算出的电导率得出的基于图像的EMA。根据从使用X射线断层扫描获得的二值化图像估算岩心样品渗透率的方法，对提出的方法进行了评估。由于它将数字图像处理与统计数据后处理结合在一起，而无需进行计算流体动力学（CFD）计算，因此具有极高的成本效益。将结果与各种岩石样品中的微型斯托克斯流量计算进行了比较。还讨论并说明了对孔离散化的敏感性。将结果与各种岩石样品中的微型斯托克斯流量计算进行了比较。还讨论并说明了对孔离散化的敏感性。将结果与各种岩石样品中的微型斯托克斯流量计算进行了比较。还讨论并说明了对孔离散化的敏感性。