| The pore structure of rock core is complex and irregular. Traditional physics, chemistry experiment is difficult to quantitatively measure and control, likely to cause deviation of measurement results. With the development of CT technology in recent years, its non-destructive, high-resolution and other features make it playing a great role in the study of pore structure. This dissertation uses the high resolution CT devices developed by China Academy of Engineering Physics for image acquisition. Images were studied from the perspective of two-dimensional and three-dimensional to get the pore structure characterization parameters.This dissertation analyzes the characteristics of CT image noise, then derive a wavelet basis, decomposition level and the threshold selection method based on wavelet theory to determine the most suitable for the sample image wavelet denoising scheme. By studying the two-dimensional CT images, porosity, pore size distribution, pore structure characterization of fractal dimension calculation method were determined. Derivation of the relationship is based on porous media model in a two-dimensional fractal porosity and fractal dimension. And as a basis to verify the two-dimensional CT images based on porosity and fractal dimension of the relationship. The results meet the requirements of porous media model.Based on the pore extraction results from two-dimensional CT images, the three-dimensional reconstruction of the voxel model were rebuilded. On this basis, body porosity, pore size distribution and fractal dimension calculation methods were derived. By using porous medium porosity model based on the fractal theory and the three-dimensional voxel model, relationship between porosity and the fractal dimension was validated, results just meet the requirements of porous media model.Finally, a pore structure characterization prototype system based on CT images was designed and implemented, which can characterize the pore structure from the perspective of 2D and 3D. |
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