Analysis of Carboniferous-Permian coal-accumulating environment and coalbed methane enrichment in the southern Qinshui Basin

Global research on the geological particularities of coal-accumulating environments and the enrichment patterns of coalbed methane (CBM) is still relatively weak. This paper studies the geological characteristics and coal accumulation patterns of Carboniferous-Permian coal-bearing seams in the southern Qinshui Basin. The results show that the coal-bearing strata in the basin represent the offshore marine and continental intercalated coal seam sediments developed. The southern part of the basin is dominated by lacustrine facies, and the delta front sub-facies is locally developed. The characteristics of coal accumulation environment in the southern Qinshui Basin are characterized by basement properties, fault networks and coal-bearing sedimentary facies, which collectively control the spatial and temporal distribution characteristics of the coal-rich belt. The differences in coal accumulation environment in the southern basin affect the tectonic evolution, the thickness of the coal seam roof and floor and the hydrogeological conditions of the coal-rich area, which further control the CBM enrichment in the Taiyuan-Shanxi Formation. The aim of this study is to explore the factors of CBM enrichment and gas control mode, so as to enrich and improve the theory and method of CBM exploration, which will also help identify the appropriate underground geological structure environment for carbon sequestration (CCS), reduce greenhouse gas emissions and effectively respond to the challenge of global warming.