Coal Engineering ›› 2025, Vol. 57 ›› Issue (8): 161-170.doi: 10. 11799/ ce202508022

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  • Received:2025-02-17 Revised:2025-06-25 Online:2025-08-11 Published:2025-09-11

Abstract:

In order to improve the degree of CBM exploration and development in the northeast of Qinshui Basin, the coal reservoir thickness and buried depth of 31 mines in the region were collected, and the a and b values, reservoir pressure, gas content, permeability, gas saturation, critical desorption pressure and porosity of coal samples were measured by isothermal adsorption test, pressure recovery curve method, calculation deduction and porosity test. Based on the structural and hydrogeological background, this paper systematically analyzes the CBM geological characteristics and the law of accumulation and accumulation in the study area, and establishes a multi-level CBM development selection evaluation index system from the perspective of CBM enrichment factors, and carries out application in the No.15 coal seam of Taiyuan Formation in the study area, and divides the favorable CBM development blocks. The results show that: No. 15 coal seam in this area has higher metamorphic conditions, with sandy mudstone and mudstone as the main surface and roof. The thickness of coal seam is between 4.30 and 8.25 m, and the average burial depth is 389 m, which belongs to medium-shallow burial depth. The average gas content is 9.37 m3/t, the adsorption capacity is strong, the average Langley pressure is 36.65 m3/t, the average permeability and porosity are poor, the average permeability is 0.029 mD, the average porosity is 5%; Coal seam gas enrichment is mainly controlled by the depth of coal seam. Compared with shallow coal seam, the thickness and porosity of deep coal reservoir have little change, and the coal reservoir pressure, gas content and Langley pressure are higher, so they have better coal seam gas storage capacity. The CBM development potential in the study area is divided into 4 categories, among which the deep buried coal seams in Pingxi and Yangquan areas are the dominant exploration and development blocks. Low Langley pressure, permeability, gas saturation and critical desorption pressure are the main disadvantages of future CBM development. The research has a certain guiding significance to the exploration and development practice of coalbed methane in the northeast of Qinshui Basin.

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