Study of digital petrophysical analysis method based on micro-focus X-ray tomography: A case study from No.3 coal seam of Bofang mining area in southern Qinshui basin

The successful application of digital rock-physical technology can not only realize the 3D spatial representation and reconstruction of pores, but also achieve the flow simulation of fluid and the comparative study of absolute permeability. Taking No.3 coal seam in Bofang mine area as the research object, in the study, a 3D digital core model was established based on micro-focus X-ray CT and image processing technology. The quantification and characterization study of the pore structure was carried out by using programming in MATLAB and various morphological algorithms contained in AVIZO, and the equivalent pore network model was established. With the perfect docking of AVIZO and COMSOL, the seepage simulation and the absolute permeability calculation in the micro-scale were realized, and the distribution of pressure field and velocity field in the process of fluid migration was discussed. The method of combining AVIZO with COMSOL enriches the research methods of rock-physical technology, which can provide a new way for studying the pore structure and fluid migration in the micro-scale.