论文部分内容阅读
系统剖析了不同层位、不同岩性煤系气源岩饱和烃与芳烃的地球化学特征,揭示了四川盆地上三叠统须家河组气源岩沉积时曾受到明显海侵事件的作用,对其源岩的生源输入与沉积环境均有较大的影响.分子地球化学特征表明:气源岩中正构烷烃存在明显的双峰态分布特征,菌、藻类生源化合物丰富,在全烃色谱图中即可辨别这些化合物的存在,反映出低等生源输入量较大;Pr/Ph比值较低,主要分布范围为0.33～0.86,平均仅0.60,与沼泽相煤系烃源岩中Pr/Ph值常大于2.0的特征完全不同,具有海相或盐湖相烃源岩的分布特点;气源岩中β-,γ-胡萝卜烷及其降解系列十分发育,在全烃色谱图中即可辨认出其存在,反映出水体的还原性较强;气源岩中甲基甾烷与甲藻甾烷十分发育、含量丰富,芳烃馏分中含硫芳烃相对丰度较高,“三芴”系列组成既不同于典型的盐湖相源岩,也与常规的沼泽相源岩存在明显差异,表明气源岩曾受到海侵作用的影响.
The geochemical characteristics of saturated hydrocarbons and aromatics in source rocks of the Upper Triassic Xujiahe Formation in Sichuan Basin are systematically analyzed. Which have a great influence on the source input and sedimentary environment of the source rock.The molecular geochemical characteristics show that there are obvious bimodal distribution characteristics of n-alkanes in the gas source rocks, rich biogenic compounds of bacteria and algae, Which can reflect the presence of these compounds, reflecting the large input of lower biogenic sources. The Pr / Ph ratio is relatively low, ranging from 0.33 to 0.86 with an average of only 0.60. Compared with the Pr / Ph The values are often greater than 2.0 with completely different features, which have the distribution characteristics of marine or salt lacustrine source rocks. The series of β- and γ-carotenoids and their degradation series in gas source rocks are well developed and can be identified in the whole hydrocarbon chromatogram Its existence reflects the strong reducibility of water body. Methylstestane and dinosterane in gas source rock are abundant and abundant, the relative abundance of sulfur-containing aromatics in aromatics fraction is higher, and the “trifluorene” series The composition is different from the typical salt lake facies source rock, also with the conventional marsh There is a clear difference between the Ze source rocks, indicating that the source rocks have been affected by transgression.