摘要
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.
The study of coalbed methane（CBM）can provide scientific basis for coalbed methane exploration and development.However,the hydrogen and carbon isotopic compositions of CBM are affected by many factors.Previous studies were mainly concerned with the influence of the properties of gas-forming parent material and maturity on the hydrogen and carbon isotopiccompositions of CBM.The influence of formation environment of gas-forming parent material on the isotopic compositions of thermogenic CBM is still unclear.Closed-system isothermal pyrolysis experiments were performed on herbaceous marsh peats derived from high latitude area with cold and dry climates and low latitude area with tropical moist climate.The hydrogen and carbon isotopic compositions and their differences of the hydrocarbon gases（methane,ethane and propane）generated during the pyrolysis of the samples were studied.The results show that the hydrocarbon gases generated from the herbaceous swamp peat in high latitude area had lighter hydrogen and heavier carbon isotopic compositions compared with those in low latitude area.At pyrolysis intervals from peat to vitrinite reflectance values（Ro）of 2.5%,3.5%and 5.5%,the differences in the averageδD values between the samples in high latitude and low latitude areas were from -17‰ to -10‰ for methane,-32‰ to -28‰for ethane and -25‰ to -17‰ for propane,and in the average δ-（13）C values between them were 2.9‰ to 3.6‰ for methane and 0.9‰ to 1.1‰ for ethane,respectively.The differences should result from the influence of climatic environment on hydrogen and carbon isotopic compositions of coal-forming original material.The relationship between Rovalues and the hydrogen and carbon isotopic compositions of gases generated by coal-forming organic matter under different climatic environments as well as the hydrogen or carbon isotopic relationships of methane and ethane were established.These results may provide a basis for studying on the genesis of coalbed gas formed by coal-forming material under different climatic environments.
作者
段毅
段明辰
吴应忠
姚泾利
罗安湘
邓秀芹
齐亚林
Duan Yi Duan Mingchen Wu Yingzhong Yao Jingli Luo Anxiang Deng Xiuqin Qi Yalin(Gansu Provincial Key Laboratory of Petroleum Resources/Key Laboratory of Petroleum Resources Research, Chinese Academy of Sciences/Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou 730000, China School of Economics and Management, Gansu Institute of Political Science and Law, Lanzhou 730070, China School of Earth Science ＆ Resources, Chang＇an University, Xi＇an 710054, China School of Earth Science, University of Chinese Academy of Sciences, Beijing 100049, China Exploration and Development Institute of Changqing Oilfield Company, CNPC, Xi＇an 710018, China)
出处
《地球科学（中国地质大学学报）》
EI
CSCD
北大核心
2017年第9期1541-1548,共8页
Earth Science-Journal of China University of Geosciences
基金
国家自然科学基金(Nos.41472121,41772108,41272125)
关键词
泥炭
模拟实验
气体产物
氢碳同位素
气候环境
煤层气成因
地球化学
peat
simulation experiment
gas product
hydrogen and carbon isotopes
climatic environment
coalbed gas origin
geochemistry
