关键词: 瓦斯赋存, 构造发育, 采动影响, 构造演化, 瓦斯运移, 数值模拟, 卸压区域

Abstract: To study the gas migration laws of coal-rock systems in structurally developed areas under mining influence, a dynamic evolution model of coal body permeability under mining influence was constructed. By combining the interaction of stress field, deformation field, and seepage field of coal-rock, the mechanism of gas migration in the coal body was analyzed in terms of fluid-solid coupling. Taking the Sangbei mining area as the engineering background, a combination of theoretical analysis, field measurement, and numerical simulation was used to analyze the influence of regional structures on gas storage in the Sangbei mining area. It was pointed out that the Sangbei integration area is located in the southeast of the Ordos Basin Yishan Slope, where the structure is complex, and its impact on gas storage in coal seams is reflected in folds, faults, and collapse column structures. Based on field measurements, it was found that the vertical and horizontal stresses at measurement point 7 are the smallest, and the vertical stress of the 8 measurement points is between 4.5MPa and 7.2MPa, increasing linearly with burial depth, mainly dominated by vertical stress. The stress is influenced by gravity and structural movements, with horizontal structural movements playing a major role. The current stress state is controlled by the most recent structural movements, and after the movement, most of the stress is released with a small amount remaining. Through the multi-field coupling model of stress-injury-seepage of gas-containing coal seams, a numerical simulation scheme was established, and different parameters were set to simulate the gas migration in coal seams under different extraction times. The results show that as the extraction time increases in the original area, the area of gas pressure change expands, in the fully unloaded area, the gas pressure decreases over time and is related to the degree of unloading, and in the structurally developed area, the change in gas pressure is affected by the degree of structural development, with the higher the degree of development, the smaller the impact.