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为了认识草本沼泽和森林沼泽成煤物质以及煤显微组分对热解煤层气同位素,特别是氢同位素的影响,对草本沼泽和森林沼泽泥炭以及具有略微不同显微组分的煤进行了热解模拟实验,研究了它们热解烃类气体氢碳同位素组成差异,以及这种差异随成熟度的变化,讨论了引起这种差异的原因。结果表明:草本沼泽泥炭热解甲烷、乙烷和丙烷δD平均值分别为-235‰、-200‰和-209‰,森林沼泽泥炭的平均值分别为-226‰、-188‰和-191‰。草本沼泽泥炭热解甲烷、乙烷和丙烷δ13 C平均值分别为-36.2‰、-27.4‰和-31.6‰,森林沼泽泥炭的平均值分别为-33.7‰、-20.7‰和-25.6‰。表现为草本沼泽泥炭热解的烃类气体氢碳同位素组成轻于森林沼泽泥炭,并且从泥炭连续热解至RO值分别为2.5%、3.5%和5.5%时,甲烷氢同位素值分别平均低18‰、11‰和9‰,碳同位素值分别平均低3.4‰、3.8‰和1.8‰。煤显微组分微小的差异对热解烃类气体碳同位素有明显的影响,表现为具有较高壳质组的煤热解甲烷的碳同位素组成较轻,可是煤热解烃类气体氢同位素组成主要与成煤环境因素有关。这些研究成果为自然煤层气的成因判识提供了科学数据。
In order to understand the effect of herbaceous and swamp coal-forming materials and coal micro-components on the pyrolysis of coal-bed gas isotopes, especially hydrogen isotopes, herbaceous and forest swamp peat and coal with slightly different microscopic components were heat-treated Decomposition experiments were carried out to investigate the differences of hydrogen and carbon isotopic compositions of pyrolysed hydrocarbon gases and the reasons for the differences with maturity. The results showed that the δD values of methane, ethane and propane for herbaceous peat pyrolysis were -235 ‰, -200 ‰ and -209 ‰, respectively. The average values of forest marsh peat were -226 ‰, -188 ‰ and -191 ‰ . The δ13C values of methane, ethane and propane for herbaceous peat pyrolysis were -36.2 ‰, -27.4 ‰ and -31.6 ‰, respectively. The average values of forest marsh peat were -33.7 ‰, -20.7 ‰ and -25.6 ‰, respectively. The hydrogen-carbon isotope composition of the pyrolysis hydrocarbon of herbaceous marsh was lighter than that of forest marsh peat, and when the peat was pyrolyzed continuously to 2.5%, 3.5% and 5.5% respectively, the hydrogen isotopes of methane were respectively 18 ‰, 11 ‰ and 9 ‰. The average carbon isotope values were 3.4 ‰, 3.8 ‰ and 1.8 ‰, respectively. The slight difference of coal microstructure has a significant effect on the carbon isotope of pyrolysis hydrocarbon gas, which shows that the coal pyrolysis methane has a lighter carbon isotope composition with higher crust group, but coal pyrogenation hydrocarbon gas hydrogen isotope The main composition and environmental factors related to coal. These research results provide scientific data for the genetic discrimination of natural CBM.