南堡凹陷下第三系烃源岩显微组分组成与热演化

MACERAL COMPOSITION AND THERMAL EVOLUTION OF LOWER TERTIARY SOURCE ROCKS IN THE NANBAO SAG

采用有机岩石学全岩光片镜鉴技术 ,系统研究了南堡凹陷下第三系烃源岩的显微组分组成、主要生烃组分及热演化。南堡凹陷烃源岩总体上具有以陆生高等植物生源的有机物质占优势 ,富含镜质组、贫惰性组的特点 ,孢子体、藻类体、壳屑体和矿物沥青基质为该区主要生烃组分。利用镜质组反射率 Ro 和富氢组分显微荧光的变化 ,讨论了南堡凹陷下第三系烃源岩有机质热演化的特征 ,初步提出了有机质热演化阶段的划分方案。

By using the technique of microscopy determination of organic petrology on whole rock surfaces,a systemical study on maceral composition,hydrocarbon- generating maceral and thermal evolution characteristics of Lower Tertiary source rocks in the Nanbao sag is carried out.In general,there are predominances of organic matter of terrestrial higher plants genetic source,and rick vitrinite,poor inertinite in source rocks of this sag.It is suggested that sporinite,alginite,liptodetrinite and mineral- bituminous groundmass are the major macerals for hydrocarbon generation.The characteristics of maceral thermal evolution of Lower Tertiary source rocks in the Nanbao sag are discussed,from the analysis of the changes of vitrinite reflectance and fluorescence alternation of hydrogen- rich macerals.The classification scheme of thermal evolution stages of organic matter in this sag is preliminarily proposed.