The paper presents a methodology for obtaining high-quality 3D models of macrocracks from X-ray computed tomography images on the example of rocks from low-permeability when modeling on specimens the method of directed unloading of the reservoir. Traditionally, a very small representative volume of rock is selected during rock micro-CT studies. However, when analyzing macrocracks, this approach is not possible due to the need to scan, process and create models of large volumes. Thus, it becomes necessary to search for efficient and resource-saving methods of working with large images, which will allow to carry out fast, high-quality image processing, create accurate models and optimize them for further calculations. The described approach includes works on obtaining, reconstruction, processing, segmentation and optimization of the created models in order to obtain the most realistic and suitable for analyzing the structures of the internal space of rocks. The work describes the results of analysis of fractures formed in the rock specimens after physical modeling of the increase well productivity method application - the directional unloading reservoir method. All stages of work with tomography images are described, and 3D models of the specimens under study are created. The orientation of fractures and their openness are analyzed, as well as the modeling of particle movement in the rock is performed to determine the characteristics of new percolation paths in the rock. The proposed methodology is designed to simplify the acquisition of high-quality 3D models of the internal space of dense geomaterials based on full-scale CT images.