3D pore network extraction in granular media by unifying the Delaunay tessellation and maximal ball methods

• Published in: Journal of petroleum science & engineering 2018-08, Vol.167, p.692-701
• Main Authors: Li, Z., Wang, Y.H., Chow, J.K., Su, Z., Li, X.
• Format: Article
• Language: English
• Subjects: Delaunay tessellation; DEM simulation; Maximal ball; Pore network extraction
• ISSN: 0920-4105; 1873-4715
• DOI: 10.1016/j.petrol.2018.04.058

In this study, a novel method for pore network extraction in the weakly consolidated media is reported, which unifies both the Delaunay tessellation (DT) and maximal ball (MB) methods in a complementary way. This unified method retains the advantages of both methods, and most importantly, eliminates the disadvantages when either the DT or the MB method is used individually. As a result of such a combination, the merging process of the Delaunay tetrahedra can be carried out in an objective way by utilizing the clustering results of maximal balls. Furthermore, the problems generated in using the maximal balls method, e.g., underestimating the throat size and producing tiny and incorrect throats, can be eliminated by incorporating the Delaunay tessellation, which enables precisely partition the pore space and accurately defining the throat size. Examination of this unified method, based on the results of pore network extraction on a sample (with a periodic boundary) before and after the triaxial shearing using DEM simulation, verifies that this method is objective and effective. The associated morphology of the pore space therefore can be accurately described in terms of the pore size, throat size and the associated distributions. This unified method also has the potential to characterize another dimension of fabric in granular media, i.e., the throat-based fabric. •Pore network is extracted by unifying Delaunay tessellation and maximal ball methods.•Pore space is partitioned into individual polyhedral void cells objectively.•Pores are contained in void cells and throats pass through common faces between cells.•Both pore and throat sizes are increased by shearing due to the dilation response.•After triaxial shearing, throat normals align more in the horizontal direction.