泌阳凹陷核桃园组湖相烃源岩微观形态特征与形成机制

利用背散射电子成像技术研究了泌阳凹陷核桃园组湖相烃源岩的微观特征,结果表明泌阳凹陷核桃园组核三段—核二段湖相烃源岩的有机质形态以条形和卵形生物碎屑为主.根据有机质在湖相烃源岩中不同的分布形式,可将泌阳凹陷核桃园组湖相烃源岩划分为含纹层状有机质烃源岩、含分散状有机质烃源岩和过渡类型烃源岩3种类型.根据烃源岩地球化学分析可知,含纹层状有机质烃源岩有机碳含量高,形成于水体盐度较高的咸水环境中,在外来径流补给较少的情况下,沉积有机质的主要来源为水生生物,干酪根主要为Ⅰ型;含分散状有机质烃源岩有机碳含量较低,沉积于水体盐度较低的淡水环境中,在外来径流补给较多的情况下,陆源生物和水生生物为沉积有机质的主要来源,干酪根类型主要是Ⅱ型;过渡类型的烃源岩其沉积环境则介于上述两者之间.

Microscopic morphology and formation mechanism of lacustrine source rocks of Hetaoyuan Formation in Biyang Sag

The study on the lacustrine source rocks of Hetaoyuan Formation in Biyang Sag was carried out by using backscattered electron imaging technology. The study results show that the shape of organic matter mainly denominated in trip, oval biological detritus. The organic matter in source rocks distributed in different forms, so according to the distribution characteristics of organic matters, the source rocks in Biyang Sag can be subdivided three types, including lamination source rocks, scattering organic matter source rocks and intermediate forms source rocks. Meanwhile, according to the analysis of geochemical data, the lamination source rocks is with high organic carbon content, formed in high salinity saltwater environment, with fewer external runoff, the main source of sedimentary organic matter is aquatic organisms, and the kerogen is mainly type Ⅰ ; scattering organic matter source rocks is with low content of organic carbon, deposited in low salinity freshwater environment, with more external runoff, the main source of sedimentary organic matter are terrestrial and aquatic organisms, and the kerogen is mainly type Ⅱ ; while the sedimentary environment of intermediate forms source rocks is intermediate between the lamination source rocks and the scattering organic matter source rocks.