Numerical 3D-modelling of Micro Scale Porosity Variations - A μ-CT Study on Permian Reservoir Sandstones

This contribution is part of the R&D “H2STORE” project. In this framework the porosity and fluid flow regime of Permian reservoir sandstones are analyzed. Different analytical methods were applied to compare these features from handspecimen- down to microscopic scales. By microscopic image and μ-CT analyses used for numerical simulation a 3D model is established, which substantiates a complex pore network. This simulation reveals very narrow laminated structures with alternating high porous and non-porous layers. However this lamination/bedding is only recognizable by sophisticated CT data processing but is almost absent in microscopic thin sections and handspecimen. Thus, in using these kinds of samples and scales the sandstone is quite homogenous, without any indications of bedding structures. In comparing porosity data achieved by different analytical methods, the high quality of the μCT data and the numerical simulation of the pore network are confirmed. The verification of very small scaled layering in supposed homogenous, massive sandstones can help to explain some unexpected fluid flow behaviour in reservoirs and will also affect reservoir injectivity. These processes have to be considered during technical storage and recovery operations, like CCS, EOR/EGR or energy/hydrogen storage, because these will induce modifications in the formerly established fluid flow regime.