Rapid multiscale pore network modeling for drainage in tight sandstone

Tight sandstone possesses multiscale pores. Capturing and modeling the important pore properties into a pore network for drainage is challenging and computationally expensive. We present a method for modeling of a multiscale pore network, which enables us to handle huge rock micro computed tomography (mu CT) images with high computational efficiency and minimal experimental input data. This method uses micro-links to represent the upscaled transport properties of micropores unresolved by the image and connects pore clusters that have topological relationships in the image to extract a connected pore network from it. The size distribution of microlinks is optimized and determined by experimental permeability. The effects of the number distribution of microlinks on flow properties are investigated to obtain the robust parameter. The presented method is validated on a digital core and the published experimental data. This method is successfully applied to rapidly evaluate the influence of mineral components on drainage behavior in two tight sandstone rocks, which involves a large number of computations. The two mu CT images both contain more than 109 voxels and are handled by a personal computer, proving the potential in rapidly, accurately, and conveniently handling huge tight sandstone mu CT image for evaluating the drainage characteristics

Multiscale pore-fracture hybrid pore network modeling for drainage in tight carbonate

Tight carbonate possesses both fractures and multiscale pores. Flow through tight carbonate rocks involves several length scales and the complicated flow physics. Capturing and modeling the entire void space into a single pore network model for drainage is challenging. Here, we present a novel method for modeling of a multiscale pore-fracture hybrid pore network, which enables various void spaces at multiple length scales and the flow characteristics in them to be included. Pores and fractures in a low-resolution CT image are extracted by medial axis-maximal ball algorithm and medial surface algorithm, respectively, to generate a pore-fracture hybrid pore network. Then, a statistics-based small-scale stochastic pore network is established in the CT image solid domains to represent the micropores unresolved by the image. The two pore networks are organically integrated into a multiscale hybrid pore network by cross-scale connections. The statistics of small-scale pore network are determined by experimental permeability. We study the effects of the small-scale pore network density on connectivity, single-and two-phase flow properties of the model to obtain the robust parameter. The influence of fractures on two-phase flow properties is analyzed. Results show the significance of incorporating fractures and micropores in the model. The model is validated via comparison between simulation result and experimental data. This method can accurately, efficiently, conveniently construct multiscale pore-fracture hybrid pore network of tight carbonate rock for evaluating the drainage characteristics

一种REV连通孔隙空间的构建方法、装置

本发明实施例涉及一种REV连通孔隙空间的构建方法、装置，所述方法包括：获取REV尺度微米CT图像；确定所述REV尺度微米CT图像中，各个微米孔隙簇之间的拓扑关系；根据各个微米孔隙簇之间的拓扑关系，按照最短路径原理在二值图像中建立纳米连接通道的中轴线以定位这些通道；以实验渗透率为约束确定所述纳米连接通道的半径，建立REV连通孔隙空间。如此基于REV尺度微米CT图像建立REV连通孔隙空间，可以反映纳米尺度孔隙空间和微米尺度孔隙空间的全部信息，并且节省经济和时间成本