3-D Pore-Scale Modelling of Sandstones and Flow Simulations in the Pore Networks

Abstract

A new method for generating realistic homogenous and heterogeneous 3-D pore-scale sandstone models is presented. The essence of our method is to build sandstone models which are analogs of actual sandstones by numerically modelling the results of the main sandstone-forming geological processes-sandgrain sedimentation, compaction, and diagenesis. The input data for the modelling are obtained from image analyses of thin section images of the actual sandstone. The spatial continuity of the sandstone model in the X, Y, and Z directions is determined using a scale-independent invasion percolation based algorithm. The resulting spatial continuity function, which is an ellipsoid, may be used as a heterogeneity descriptor for the sandstone model. Heterogeneity analyses show that compaction reduces the spatial continuity in the horizontal direction more rapidly than in the vertical one. The architecture and geometry of the network representation of the pore space are determined by applying various 3-D image analysis algorithms directly on the fully characterised sandstone model. A 3-D pore network which was generated from thin section data from a strongly water wet Bentheimer sandstone is used as input to a two-phase network flow simulator. Simulated transport properties for the sandstone model are in good agreement with those determined experimentally.

Predictive pore‐scale modeling of two‐phase flow in mixed wet media

“…[6] Øren and coworkers at Statoil have extended this approach to a wider range of sedimentary rocks [Bakke and Øren, 1997;Øren et al, 1998]. For more complex sandstones it is usually necessary to create first a 3-D voxel based representation of the pore space that should capture the statistics of the real rock.…”

“…For more complex sandstones it is usually necessary to create first a 3-D voxel based representation of the pore space that should capture the statistics of the real rock. This can be generated directly using X-ray microtomography [Dunsmuir et al, 1991;Spanne et al, 1994], where the rock is imaged at resolutions of around a few microns, or by using some statistical [Adler and Thovert, 1998] or object-based [Bakke and Øren, 1997] reconstruction technique. From this voxel representation an equivalent network of pores and throats can be extracted [Lindquist et al, 1996; Bakke and Øren, 1997; Delerue and Perrier, 2002].…”

Characterising the Morphology of Disordered Materials

“…We note that the microstructure of a sandstone is a result of a complex physical process, which can include consolidation, compaction and cementation of an original grain packing. More complex and realistic models of sandstones have been derived [4,40]. These methods require however, the simulation of the generating process including primary grain sedimentation followed by a diagenetic process such as compaction and cementation.…”

Investigation of permeability, formation factor, and porosity relationships for Mesaverde tight gas sandstones using random network models

“…In complex sandstones, it is recommended to create first a 3D image-based representation of the pore space that should capture the statistics of the real rock. This can be generated using a direct imaging technique such as micro-CT scanning (Okabe and Blunt 2005), or by various process/object-based modeling approaches (Bakke and Ö ren 1997;Ö ren et al 1998;Bakke 2002, 2003). Subsequently, using various image-based network extraction techniques (Al-Kharusi and Blunt 2007;Dong and Blunt 2009), an equivalent pore network is then extracted from the 3D image to estimate the single and multiphase fluid flow properties.…”