Distribution characteristics of isotope carbon and its geological origin in coal & gas carbon of Qidong coal mine, Huaibei coalfield

Based on stable organic carbon isotopic analysis for 24 coal sample and 12 gas samples from six coal seams in Qidong coal mine, Huaibei coalfield, the paper has studied distribution characteristics and variation trend of the coal and gas carbon isotope, providing the theoretical basis for the analysis of different coal seams and gas sources. The study shows:Variation range of δ¹³C is -22.76‰~-25.11‰. δ¹³C value in coal seams 6-1 to 9 presents undulated variation, probably influenced by the coal depositional environment; Variation range of methane δ¹³C₁ is -52.51‰~-63.65‰, The variation range of δ¹³C₁ is characterized by containing secondary biogenic gas. And the CO₂ carbon isotopic values (-22.61‰~-17.96‰) demonstrated that CO₂ in methane was resulted from coal pyrolysis.