Abstract:
Identifying the in gas control geological types and different gas production characteristics during coalbed methane well co-production provides important guarantees for the rational deployment of well locations. The No.3+4 and No.15 coal seams in Wulihou Mine are taken as the research object. Based on previous coalbed methane exploration and development data, the Kriging interpolation method is used to obtain the distribution characteristics of main reservoir parameters such as gas content, burial depth, and coal thickness in the No.3+4 and No.15 coal seams. The controlling effects of factors such as burial depth, coal thickness, faults, groundwater potential, and roof and floor lithology on gas content are analyzed, and different gas control geological types are classified. Based on the production law of multiple gas sources in combined layer drainage, the differences in gas production characteristics under different gas control geological types are compared, and corresponding development suggestions are proposed. The results show that the gas control geological types can be divided into four types: fault control type, burial depth control type, groundwater potential control type, and roof and floor lithology control type based on the spatial distribution of the main reservoir parameters in the No.3+4 and No.15 coal seams. The main control type of fault causes the escape of nearby coalbed methane, resulting in low coal seam gas content and daily gas production. For the buried depth control type, the gas occurrence time is late and the stable gas production is low. The main control type of groundwater potential is characterized by weak hydrodynamics, high gas content, strong flow conductivity, and high daily gas production. For the roof and floor lithology control type with a mudstone roof, the gas occurrence time is early, and stable gas production is relatively high. When the fault is within 200 m and the burial depth is less than 550 m, well layout should be cautious. If the burial depth is greater than or equal to 550 m and there are no fault areas, priority should be given to coalbed methane development. For areas with high groundwater potential, the hydrodynamic retention area or the mudstone roof area is selected as the priority area.