Reconstruction Of Coal Pore Structure Model And Seepage Simulation Based On CT Imaging

Coal is a material with a porous medium.Coal contains natural fissures,which are influenced by bedding structure and crustal movement.During this process,coal gradually evolved into secondary fractures based on natural fractures.The arrangement of crack pores is very complex and irregular.Secondary cracks and natural cracks affect the physical and chemical properties of coal.It is difficult to explore the true pore and fracture structure of the coal body in macro-physical experiments and micro-simulations.In this paper,The image analysis software is used to perform a series of processing such as cropping,median filtering,noise reduction processing and binarization processing on the obtained original image to obtain a coal skeleton,the coal body is constructed into two-dimensional model and three-dimensional model,providing an effective method to describe the construction of micro-pore structure.In order to explore the pore seepage law from the real micro-scale.By means of comparison of experiment and simulation,the flow process of water in different pore and fracture structures was studied,and the flow law of coal seepage water in micro scale was revealed.Only by understanding the movement mode of fluid in the coal pores and the extent and distribution of fluids in coal at the microscopic scale can we fundamentally understand the mechanism of coal injection.In order to find a more effective method of coal seam water injection.The research in this paper is mainly divided into the following parts:(1)Micro-CT scanning of selected coal samples before and after water injection is carried out respectively,and the original data image of coal body is obtained.The acquired image is processed by means of median filtering,binarization and gray histogram with MATLAB software.After processing,an image that can be modeled is obtained.(2)Calculate the porosity of each section of the coal body and the porosity of the whole coal body by the frequency of the pixel values of the gray histogram and the inversion by mathematical statistics.(3)Using the interpolation function in COMSOL simulation software to reconstruct the image of the median filter,the model includes the information of each point on the processed image,and the two-dimensional model of the coal body is represented by real and non-destructive.The porosity of the coal body and the movement law of the seepage water in the coal body were calculated by simulation.(4)Based on the pore reconstruction method,the AVIZO software was used to extract the three-dimensional model of the coal body,the real pore structure model,and the coal water distribution model after the experimental water injection.The flow process and law of water in coal under real experimental conditions are analyzed,and the flow velocity,direction and occurrence range of water in different pore structures are studied.This thesis has 23 figures,3 tables and 58 references.