中上扬子地区二叠系烃源岩特征

Characteristics of the Permian Source Rocks in the Middle and Upper Yangtze Region

基于烃源岩的类型、分布,有机质的丰度、成熟度等方面的分析,对中上扬子地区二叠系烃源岩的特征进行了详细研究,并对烃源岩发育的控制因素进行了探讨。研究表明:中上扬子地区二叠系烃源岩主要为暗色碳酸盐岩、暗色泥(页)岩和煤,薄层硅岩也是潜在的烃源岩;其中中二叠统烃源岩以暗色碳酸盐岩为主,上二叠统烃源岩以暗色碳酸盐岩和暗色泥(页)岩为主;栖霞阶和茅口阶烃源岩厚度较大,分布较广;吴家坪阶和长兴阶烃源岩厚度相对较小,分布相对较局限;川西北—川东北—渝东—鄂西—黔北—黔中地区是各阶烃源岩分布的叠合区,是有利的生烃区带;研究区二叠系烃源岩的发育与沉积环境和上升流作用的关系密切,沉积环境控制着烃源岩的岩石类型和有机质丰度,中二叠统优质烃源岩的发育还与上升流的作用有关。

Based on the analysis of the types and distribution of source rocks and the abundance and maturity of organic matter,the characteristics of the Permian source rocks in the Middle and Upper Yangtze Region were studied in detail,and the controlling factors of the development of the source rocks were discussed.The results show that the Permian source rocks in study area are mainly composed of dark carbonate rocks,dark mudstones or shale and coal,and the thin-bedded siliceous rocks are also potential source rocks.The thickness of the source rocks of the Qixia Stage and the Maokou Stage is rather thick with wide distribution,and the thickness of the source rocks of the Wujiaping Stage and the Changxing Stage is relatively thin with rather limited distribution;and the area of northwestern Sichuan-northeastern Sichuan-eastern Chongqing-western Hubei-northern Guozhou-central Guizhou is the superimposed area of source rocks of the four stages,where is the favorable hydrocarbon zone.The development of the source rocks of the Permian in the study area is controlled by the sedimentary environment and the action of the upwelling.The types of source rocks and abundance of organic matter are mainly controlled by the sedimentary environments;and the development of the high-quality source rocks of the Middle Permian is closely related to the upwelling.