Genesis of Calcite Veins in 8# Coal Seam of the Upper Carboniferous Benxi Formation, Southeastern Margin of Ordos Basin

The 8# coal seam in the Benxi Formation of southeastern margin Ordos Basin is a deep with abundant coalbed methane resources. Calcite veins are commonly developed within seam, and their formation processes mechanisms have significant implications for enrichment methane. Genesis calcite was analyzed to reveal impact on accumulation, an integrated application petrographic study by thin section, cathodoluminescence analysis, carbon-oxygen isotope homogeneous temperature measurements fluid inclusions. research findings indicate that can be classified into three stages: C1, C2, C3. diagenetic fluids C1 primarily originated from contemporaneous seawater. responsible C2 consist organic enriched biogenic gas, whereas contributing C3 associated liquid hydrocarbons form decarboxylation matter. Furthermore, development both influenced hydrothermal resulting tectonic heating events during Early Cretaceous. By combining analysis hydrocarbon accumulation history burial area, it has been established occurred Late Triassic Jurassic, while took place Jurassic exploration production practices area firmly crucial significance evolution migration outcomes provide valuable insights areas.