摘要
柴达木盆地北缘地区侏罗系(中下侏罗统)的优质烃源岩主要发育于湖相与三角洲相环境。研究了不同时代、不同沉积环境中烃源岩的生物标志物组成特征,结果发现,有3类化合物的分布与组成差异显著,包括三环萜烷(C19、C20、C21)的分布型式、重排藿烷的丰度以及规则甾烷的相对组成。其中,不同时代的差异主要体现在规则甾烷组成上;而不同沉积环境的差异主要体现为三环萜烷(C19、C20、C21)的分布型式及重排藿烷的丰度。分析认为,这些差异与烃源岩的沉积环境及其生源组成有密切关系。据此,初步将这些参数应用于两方面研究,一是为划分地层沉积环境提供"生物标志物相标志",二是研究油源对比,取得良好效果。因此,本文研究结果具有重要实用价值与参考意义。
The Jurassic organic-rich mudstone source rock in the northern Qaidam Basin occurred mainly in lacustrine and deltaic sedimentary environments. This paper focuses on the characters of biomarrker composition in these two different environments and thus seven typical samples were collected from the two settings for this purpose. The results indicate that the distribution and composition of the three kinds of compounds are very different, especially the distribution of tricyclic terpane, abundance of diahopanes, and a relative composition of regular sterrane. The composition of regular sterane suggests the different times, while distribution pattern of tricyclic terpane and abundance of diahopanes indicate the discrepancies of sedimentary environments. In deltaic source rocks, distribution of tricyclic terpane follows the order of C19 〉C20〉C21, with a relatively high abundance of diahopanes. In contrast, in lacustrine source rocks, the distribution of tricyclic terpane shows C19 〈C20〈C21 , with a relatively low abundance of diahopanes, he content of regular sterane C27 is more than 40% among sterane C27, C28 and C29 in the Middle Jurassic source rocks, but not in the Lower Jurassic rocks. These biomarker differences can be interpreted to be related to the sedimentary environments and their associated organic compositions. This study can be used in the following two aspects; one is to provide the biomarker signatures for identification of sedimentary environment; the other is to improve the understanding of oil source. Therefore, this study is of great reference significance in practical production.
出处
《地质学报》
EI
CAS
CSCD
北大核心
2008年第8期1121-1128,共8页
Acta Geologica Sinica
基金
国家自然科学基金项目(编号40602014
40638042)资助的成果
