四川盆地上三叠统须家河组煤系气源岩芳烃地球化学特征

Geochemical characteristics of aromatic hydrocarbons of coal-bearing gas source rocks from Upper Triassic Xujiahe Formation in Sichuan Basin

通过对四川盆地须家河组33个煤系气源岩芳烃馏分GC-MS分析与研究,揭示出研究区煤系气源岩芳烃的组成特征与典型的煤系源岩存在显著差异。主要表现为芳烃组成中表征高等植物生源输入的卡达烯、惹烯、1,2,5-三甲基萘、1,2,5,6-四甲基萘等化合物含量极低;而三芴系列相对百分含量表现出高硫芴与芴、低氧芴的特征,与典型煤系烃源岩中高氧芴含量之特征差异迥然。造成四川盆地须家河组煤系气源岩芳烃组成的特殊性原因可能与该地区曾经遭受过海侵作用和高热演化有关。

Thirty three coal-beating gas source rock samples from the Upper Triassic Xujiahe Formation in the Si- chuan Basin were analyzed by GC-MS. The results show that the concentration of cadalene, retene, 1,2,5-tri- methylnaphthalene and 1,2,5,6-tetramethylnaphthalene derived from terrigenous higher plant organic matter of the coal-beating gas source rocks are extremely lower than those of the typical coal-bearing source rocks. The relative contents of dibenzothiophenes and fluorenes are higher while the relative content of dibenzofurans is lower com- pared to the high content of dibenzofurans in typical coal-bearing source rocks. The particular distribution may be explained by transgression effect and high maturity.