吐哈盆地煤成油的同位素地球化学证据

EVIDENCE OF ISOTOPE GEOCHMISTRY OF COAL- GENERATED OIL FROM TURPAN- HAMI BASIN

分析了吐哈盆地原油和下侏罗统煤系源岩全烃、族组分和正构烷烃分子碳同位素 ,并与国内外已知煤成油进行了对比研究 ,旨在为吐哈盆地煤成油提供同位素地球化学证据。研究表明 :吐哈盆地原油 δ13C分布于 - 2 5.1‰～ - 2 7.8‰之间 ,平均值 - 2 6.6‰ ( 4 7) ;与中下侏罗统煤系源岩氯仿沥青“A”δ13C分布范围和平均值基本一致 ;与国内外已知煤成油 δ13C可以对比 ;原油 δ13C饱 分布于 - 2 5.2‰～ - 2 8.2‰之间 ,平均值 - 2 6.9‰ ( 2 8) ;δ13C芳 位于 - 2 4 .7‰～ - 2 7.1‰范围 ,平均值在- 2 5.9‰ ( 2 7) ;δ13C非 的分布范围为 - 2 5.1‰～ - 2 7.3‰ ,平均值 - 2 6.3‰ ( 2 6) ;δ13C沥 分布在- 2 5.2‰～ - 2 8.1‰范围 ,平均值 - 2 6.9‰ ( 2 1) ;与氯仿沥青“A”族组分 δ13C的分布范围与平均值基本相似 ;与我国已知煤成油 δ13C饱 和 δ13C芳 的分布范围和平均值也类似 ;原油正构烷烃分子碳同位素具有随碳数增大而变轻的特征 ;C7～ C2 7正构烷烃δ13C大致分布于 - 2 2‰至 - 32‰之间 ;氯仿沥青“A”正构烷烃分子碳同位素基本落在原油正构烷烃分子碳同位素的分布范围内 ;与我国已知煤成油类似 ,因此 。

We analyzed the carbon isotopes of the whole hydrocarbons,group conpositions and alkane molecules of the oil and the source rocks from Turpan- Hami Basin,compared them with those of the known coal- generated oil and tried to provide original evidence of isotope geochemistry for the oil.The results show that ( 1) theδ13C values of the oil range from - 2 5.1‰ to - 2 7.8‰ ,averaging - 2 6.6‰ ( 4 7) ,which are similar to those of the extracts of the source rocks and can be compared with those of the known coal - generated oil found at home and abroad,( 2 ) the range and average of theδ13C values of the oils are from - 2 5.2‰ to - 2 8.2‰ and - 2 6.9‰ for saturated hydrocarbons ,from - 2 4 .7‰ to 2 7.1‰ and - 2 5.9‰ ( 2 7) for aromatic hydrocarbons,from - 2 5.1‰ to - 2 7.3‰ and - 2 6.3‰ ( 2 6) for nonhydrocarbons,and from - 2 5.2‰ to - 2 8.1‰ and - 2 6.9‰ ( 2 1) for asphaltenes respectively,which resemble those of the source rocks and the found oils in China and abroad ,( 3) theδ13C values of the C7～ C2 7alkane molecules of the oils have a tendency of enlightment and a range from - 2 2‰ to - 32‰ ,which also distributes in the range of those of the source rocks and the explored oils in China.The evidence of isotope geochemistry above confirms that the oils from the Turpan- Hami Basin are certainly coal- generated