泌阳凹陷西部原油芳烃组成特征及意义

泌阳凹陷西部井楼和古城地区原油均遭受了中等—严重的生物降解，很多饱和烃生物标志化合物参数很难真实地反映它们的成因、成熟度等特征，也难以建立原油的分类方案。为此，采用GC-MS分析技术，对研究区11个原油样品的芳烃化合物进行了检测，详细分析了其芳烃地球化学特征。利用芳烃的总体分布特征图、(C20+C21)-三芳甾烷/∑三芳甾烷与C20/（C20+C28R）-三芳甾烷关系图以及(C20+C21)-三芳甾烷/∑三芳甾烷将研究区原油分为2种类型，即“后峰型”（第1类原油）和“前峰型”（第2类原油），与饱和烃中抗生物降解能力较强的生标参数C24四环萜烷/C26三环萜烷关系图分类结果完全一致。根据三芳甾烷成熟度参数判识“后峰型”原油为低熟油、“前峰型”原油为成熟油。

GEOCHEMICAL CHARACTERISTICS AND SIGNIFICANCE OF AROMATIC HYDROCARBON IN CRUDE OIL FROM THE WEST AREA OF BIYANG SAG

It is difficult to identify the characteristics of the different level biodegraded oil in Gucheng and Jinglou of the west of Biyang Sag oil by most of the saturated hydrocarbon biomarker parameters，such as the organic matter input，depositional environment and maturity of organic matter etc，and also the classification of the biodegraded oil can not be established well for this area.The aromatic compounds of 11 oil samples from the area are tested by using GC-MS analytical technique.The geochemical characteristics of aromatic hydrocarbon fraction in biodegraded oil are analyzed in detail.The results show that the biodegraded oils from the west area of Biyang Sag can be divided into two types by the component of aromatic hydrocarbon of the oil and the relation of triaromatic sterane （C20+C21） /∑（C20~C28） and triaromatic sterane C20/（C20+C28R） of crude oils.It is the same with the result by the relation of triaromatic sterane （C20+C21）/∑（C20~C28） and C24 tetracyclic terpane/C26 tricyclic terpane of crude oil.The relative level of thermal maturity of these two types of biodegraded oil is assessed by the triaromatic sterane parameters.The triaromatic sterane parameters may have significance in several aspects such as oil genesis and maturity evalution etc.