基于微焦点显微CT技术的不同煤体结构煤的孔裂隙定量表征
Quantitative Characterization of Pore Fissures for Different Coal Structures Based on μCT
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摘要: 基于微焦点显微CT技术，采用三维CAD模型和立体模型实现了不同煤体结构煤孔裂隙的三维建模，定量表征了不同尺度下原生结构煤和构造煤的孔裂隙形态、大小和空间配置，评价了煤体的渗透性能。结果表明：原生结构煤孔裂隙空间发育方位和矿物充填程度决定渗透性的各向异性；相比原生结构煤，碎裂煤裂隙宽度、密度增大，孔隙度和比表面积升高，逾渗概率最高，微区内不同方向孔裂隙连成不同级别、不同组态的孔裂隙网络，从而提升了气体渗流能力；糜棱煤形成孤立分布的孔裂隙结构，空间分布非均质性高，逾渗概率最低。研究认为，与传统方法相比，虽受到空间分辨率（1 μm）的精度制约，但微焦点显微CT技术具有无损探测构造煤内部三维孔裂隙结构特征的优势。Abstract: Based on μCT technology, three-dimensional CAD model and three-dimensional model are adopted to realize the three-dimensional modeling of coal pore cracks in different coal structures. We quantitatively characterized the pore fracture morphology, size and space configuration of primary structural coal and structural coal at different scales, and evaluated the permeability of coal. The results show that the spatial development orientation and mineral filling degree of pore fissures of primary structural coal determine the anisotropy of permeability; in comparison of primary structural coal, the fracture width and density of broken coal increased, the porosity and specific surface area increased, and the probability of permeability was the highest, and the fractures in different directions in the micro area were connected into the pore fissure network with different levels and configurations to improve the gas seepage capacity; mylonitic coal forms an isolated pore fissure structure with high spatial heterogeneity and lowest percolation probability. Compared with the traditional method, the study concludes that although the accuracy of spatial resolution (1 μm) is limited, the μCT technology has the advantage of nondestructive detection of structural characteristics of three-dimensional hole cracks in structural coal.
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Keywords:
- coalbed methane /
- coal-body structure /
- μCT /
- fracture /
- pore
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