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煤层气的成因研究可以为煤层气勘探与开发提供科学依据,然而,煤层气的氢碳同位素组成受多种因素的影响,以前较多的研究是成气母质性质和成熟度对煤层气氢碳同位素的影响,对于成煤物质形成的气候环境对热解煤层气同位素的影响尚不清楚.热解模拟了高纬度寒冷干旱和低纬度热带湿润环境的草本泥炭,对热解烃类气体的氢碳同位素组成及其差异性进行了研究.研究结果表明:与低纬度热带湿润环境中形成的草本泥炭相比较,高纬度寒冷干旱环境的草本泥炭热解甲烷、乙烷和丙烷具有轻的氢同位素组成和重的碳同位素组成,并且从泥炭连续热解至Ro分别为2.5%、3.5%和5.5%时,甲烷、乙烷和丙烷δD值分别平均降低-17‰~-10‰、-32‰~-28‰和-25‰~-17‰,甲烷和乙烷δ13 C值分别平均升高2.9‰~3.6‰和0.9‰~1.1‰.认为这种同位素差异起因于气候环境对形成泥炭的植物氢碳同位素组成的影响.建立了高纬度寒冷干旱和低纬度热带湿润环境中形成的成煤有机质热解烃类气体氢碳同位素组成与Ro之间的关系式,同时也建立了烃类气体的碳和氢同位素之间的关系式.这些研究成果为不同气候环境下形成的成煤有机质生成的煤层气成因研究提供了科学依据.
However, the composition of hydrogen and carbon isotopes of CBM is affected by many factors. Previously, more studies have focused on the nature and maturity of CBM for the hydrogen-carbon The effect of isotopes on the isotopic composition of pyrolyzed coalbed methane is not yet clear for the climatic environment formed by the coal-forming material.The pyrolysis simulates herbaceous peat in the cold, dry and low latitudes of tropical humid environment at high latitudes, Carbon isotope composition and their differences were studied.The results showed that herbaceous pyrolysis of methane, ethane and propane in the cold and arid environment at high latitudes had light hydrogen isotopes compared with the herbaceous peat formed in a tropical humid environment at low latitudes Composition and heavy carbon isotope composition, and δD value of methane, ethane and propane decreased by -17 ‰ ~ -10 ‰ and -32 ‰ on average, respectively, from continuous peat pyrolysis to 2.5%, 3.5% and 5.5% Ro respectively ~ -28 ‰ and -25 ‰ ~ -17 ‰ respectively, while the δ13C values of methane and ethane increase by 2.9 ‰ ~ 3.6 ‰ and 0.9 ‰ ~ 1.1 ‰, respectively. This difference in isotope composition is thought to be caused by climate change in peat-forming plants Hydrogen carbon The relationship between hydrogen and carbon isotope composition and Ro of hydrocarbon-forming pyrolysis hydrocarbon gases formed in cold, arid and low-latitude tropical humid environments at high latitudes was established, and the relationship between carbon and carbon And hydrogen isotopes.These results provide a scientific basis for the study of the genesis of CBM formed by coal-forming organic matter under different climatic conditions.