Digital Rock Physics: A Geological Driven Workflow for the Segmentation of Anisotropic Ruhr Sandstone

Abstract

Over the last 3 decades, Digital Rock Physics (DRP) has become a complementary part of the characterization of reservoir rocks due to the non-destructive testing character of this technique. The use of high-resolution X-ray Computed Tomography (XRCT) has become widely accepted to create a digital twin of the material under investigation. Compared to other imaging techniques, XRCT technology allows a location-dependent resolution of the individual material particles in volume. However, there are still challenges in assigning physical properties to a particular voxel within the digital twin, due to standard histogram analysis or sub-resolution features in the rock. For this reason, high-resolution image-based data from XRCT, transmitted-light microscope, Scanning Electron Microscope (SEM) as well as geological input properties like geological diagenesis, mineralogical composition, sample’s microfabrics, and estimated sample’s porosity are combined to obtain an optimal spatial segmented image of the studied Ruhr sandstone. Based on a homogeneity test, which corresponds to the evaluation of the gray-scale image histogram, the preferred scan sample sizes in terms of permeability, thermal, and effective elastic rock properties are determined. In addition, these numerically derived property predictions are compared with laboratory measurements to obtain possible upper limits for sample size, segmentation accuracy, and a geometrically calibrated digital twin of the Ruhr sandstone. The comparison corresponding gray-scale image histograms as a function of sample sizes with the corresponding advanced numerical simulations provides a unique workflow for reservoir characterization of the Ruhr sandstone.

Exploring microstructure and petrophysical properties of microporous volcanic rocks through 3D multiscale and super-resolution imaging

“…We explored how the porosity changes with thresholding variations from the Otsu value. Otsu thresholding, in fact, proved to be among the best possible approaches to capture textural features of our rocks without further geological verifications (for details on geological driven workflows for rock segmentation please refer to Balcewicz et al 35 ). Our data shows that HR and VHR scans provide porosity values little affected by user/algorithm-selected parameters, while LR scan is very sensitive to threshold variations (Fig.…”

On Frequency-Dependent Rock Experiments: A Comparative Review

“…Zhang and Toksöz [203], Das et al [204], and Jänicke et al [205] used similar Digital Rock Physics (DRP) approaches to study attenuation mechanisms and fluid-solid interactions. Balcewicz et al [206] used DRP to study other properties. Focusing on enhancing an existing FO approach, Sun et al [116] tried to alleviate the experimental destructive subsonic resonances via numerical modelling to redefine their apparatus design.…”

Digital Rock Physics in Cuttings Using High-Resolution Thin Section Scan Images

“…It utilizes non-destructive methods to determine petrophysical properties. X-ray computed tomography (CT) or micro-computed tomography (micro-CT) are widely used to create three-dimensional (3D) rock volumes, serving as digital replicas of the materials under investigation [2][3][4][5][6]. These 3D volumes are typically employed for porosity computation through segmentation and for numerical simulations of permeability using the lattice Boltzmann method, which requires powerful and expensive high-performance computing clusters [7][8][9].…”

“…These 3D volumes are typically employed for porosity computation through segmentation and for numerical simulations of permeability using the lattice Boltzmann method, which requires powerful and expensive high-performance computing clusters [7][8][9]. In parallel, scanning electron microscopy (SEM) has demonstrated that not only 3D volumes but also 2D images can serve as supplementary aids to the 3D data [2,3,7,10]. SEM has also enabled the use of thin sections, which are prepared from rocks (plugs, cuttings) and do not possess a cylindrical shape, making them more suitable for CT and micro-CT analysis.…”