Construction of pore structure and lithology of digital rock physics based on laboratory experiments

Abstract

The development and stimulation of oil and gas fields are inseparable from the experimental analysis of reservoir rocks. Large number of experiments, poor reservoir properties and thin reservoir thickness will lead to insufficient number of cores, which restricts the experimental evaluation effect of cores. Digital rock physics (DRP) can solve these problems well. This paper presents a rapid, simple, and practical method to establish the pore structure and lithology of DRP based on laboratory experiments. First, a core is scanned by computed tomography (CT) scanning technology, and filtering back-projection reconstruction method is used to test the core visualization. Subsequently, three-dimensional median filtering technology is used to eliminate noise signals after scanning, and the maximum interclass variance method is used to segment the rock skeleton and pore. Based on X-ray diffraction technology, the distribution of minerals in the rock core is studied by combining the processed CT scan data. The core pore size distribution is analyzed by the mercury intrusion method, and the core pore size distribution with spatial correlation is constructed by the kriging interpolation method. Based on the analysis of the core particle-size distribution by the screening method, the shape of the rock particle is assumed to be a more practical irregular polyhedron; considering this shape and the mineral distribution, the DRP pore structure and lithology are finally established. The DRP porosity calculated by MATLAB software is 32.4%, and the core porosity measured in a nuclear magnetic resonance experiment is 29.9%; thus, the accuracy of the model is validated. Further, the method of simulating the process of physical and chemical changes by using the digital core is proposed for further study.

Research on a New Reconstruction Technology and Evaluation Method for 3D Digital Core Pore Structure

“…The accuracy of the digital core is a necessary condition for seepage simulation and research into the mechanism behind microscopic seepage. In the field of digital core technology, the preprocessing of the original core image, the collection of porous media characteristics from the original core image, the reconstruction of the digital core, and the evaluation of the digital core are essential aspects of establishing an accurate digital core (Huang et al, 2021). Presently, the methods of evaluating digital cores mainly detect digital cores through functions such as the autocorrelation, variation, pore size distribution, and local porosity distribution functions.…”

Research and Implementation of Three-Dimensional Spatial Information Characterization and Visualization of Fractures in Deteriorated Sandstone

“…With the emergence of 3D laser scanners and photogrammetry scanners, 3D point cloud data reconstruction has also achieved rapid development. Huang [21] studied the distribution of minerals in the rock core by X-ray diffraction technique combined with CT scan data. Fang [22] made a 3D reconstruction of the coal pore network through CT scan data, which provides a theoretical basis for the study of digital rock physics.…”

Study on Oil Recovery Mechanism of Polymer-Surfactant Flooding Using X-ray Microtomography and Integral Geometry

“…The X-ray microtomography, for short, micro-CT, as an efficient nondestructive imaging tool, can obtain reliable gray images of rock samples with sub-micron resolution. The micro-CT has been widely involved in reservoir properties evaluation [ 16 , 17 , 18 , 19 , 20 , 21 ], multiphase fluid flow [ 22 , 23 , 24 , 25 , 26 ], enhanced oil recovery and CO 2 geological storage [ 27 , 28 , 29 , 30 , 31 , 32 ].…”