Distribution and Composition of Biomarkers in Crude Oils from Different Sags of Beibuwan Basin
-
摘要: 通过对取自北部湾盆地不同凹陷典型原油样品中各类生物标志物的分布与组成特征的系统分析，发现盆地北部的涠西南凹陷和乌石凹陷所产原油具有姥植比低和奥利烷与各类重排构型生物标志物含量低，而C26+长链三环萜烷系列和C304甲基甾烷含量高的特点，且其三环萜烷系列呈现以C23为主峰的正态分布，指示了该类原油的烃源岩沉积时水体较深，还原性相对较强，且原始生烃母质以藻类为主；而南部福山凹陷和迈陈凹陷所产的原油则具有姥植比高和奥利烷与各类重排构型生物标志物含量高的特征，而C26+长链三环萜烷系列和C304甲基甾烷含量低，且其三环萜烷系列呈现C19—C26阶梯状依次降低，表明这类原油的烃源岩沉积时水体较浅，还原性相对较弱，且原始生烃母质中被子植物来源的陆源有机质贡献较大。由此表明北部湾盆地南北不同凹陷第三纪的沉积特征和有机质生源构成存在显著差异。Abstract: Various biomarkers in some typical oils from different sags, Beibuwan Basin, have been analyzed, in this paper. The results show that the crude oils from Weixinan Sag and Wushi Sag in the northern basin have relatively lower Pr/Ph ratio, low abundance of oleanane and various rearranged configuration biomarkers, but higher abundance of C26+ long chain tricyclic terpanes with normal pattern in C23 highest peak and C30 4methyl steranes, indicating that their source rocks were deposited under relatively deep and reduced environment with significant algae input. Bun for the crude oils from Fushan Sag and Maichen Sag in the southern basin, it is characteristic of relatively higher Pr/Ph ratio, higher abundance of oleanane and various rearranged configuration biomarkers, but lower abundance of C26+ long chain tricyclic terpanes with steplike decreasing pattern of C19—C26 and C30 4methyl steranes, showing that their source rocks were deposited under relatively shallow and oxidized environment with significant organic matter input from angiosperms. It implies that for northern sags and southern sags in Beibuwan Basin, there are some obvious differences in the depositional environment and organic matter input.
-
Key words:
- Beibuwan Basin /
- crude oil /
- biomakers /
- 4methylsteranes /
- oleanane /
- diahopanes /
- diasteranes
-
点击查看大图
计量
- 文章访问数: 1682
- HTML全文浏览量: 9
- PDF下载量: 657
- 被引次数: 0
下载:
