羌塘盆地双湖地区索瓦组烃源岩芳烃地球化学特征及意义

Geochemical characteristics and significance of aromatic hydrocarbons in the Suowa Formation source rocks in the Shuanghu area,Qiangtang Basin

为认识羌塘盆地双湖地区索瓦组烃源岩有机质来源、沉积环境及成熟度,本研究采用抽提分离和气相色谱-质谱联用等技术分析了双湖地区索瓦组烃源岩中芳烃类化合物地球化学特征。结果表明,双湖地区索瓦组烃源岩中存在较高丰度的1,2,5-三甲基萘、9-甲基菲、惹烯、?及三芳甾烷系列化合物等,指示了高等植物的母质来源。三芴、二苯并噻吩及三芳甾烷系列化合物的分布特征指示索瓦组烃源岩沉积于还原环境。萘、菲、二苯并噻吩及三芳甾烷系列化合物等成熟度参数表明,羌塘盆地双湖地区索瓦组烃源岩已达到成熟阶段。综合有机质丰度及类型分析,认为羌塘盆地索瓦组烃源岩具有一定油气资源勘探价值。

In order to understand the source of organic matter,sedimentary environment,and maturity of the Suowa Formation source rocks in the Shuanghu area,Qiangtang Basin,the geochemical characteristics of aromatic compounds in the source rocks were analyzed using extraction fractionation and gas chromatography-mass spectrometry.The results show that the source rocks of the Suowa Formation in the study area have high abundances of 1,2,5-trimethylnaphthalene,9-methylphenanthrene,retene,chrysene series compounds,and triaromatic steroids,indicating a source of higher plants.The distribution characteristics of trifluorene,alkyl dibenzothiophene,alkyl dibenzofuran,and triaromatic steroids indicate a reductive sedimentary environment for the Suowa Formation.A comprehensive study of the maturity parameters of alkylnaphthalene,alkylphenanthrene,alkyldibenzothiophene,and triaromatic steranes showed that the Suowa Formation source rocks in the Shuanghu area of the Qiangtang Basin have reached maturity stage.Based on a comprehensive analysis of the abundances and types of organic matter,it is concluded that the source rocks of the Suowa Formation in the Qiangtang Basin have a certain exploration value for oil and gas resources.