湘鄂—江南隆起区寒武系黑色页岩有机地球化学特征

Characteristics of Organic Geochemistry of Cambrian Black Shale in Hunan and Hubei Provinces-Jiangnan Uplift

我国南方页岩气藏发育的最有利区位于四川盆地、米仓山—大巴山前陆以及渝东、黔北、湘鄂—江南隆起北缘一线,寒武系地层普遍发育黑色泥页岩,这套黑色泥页岩是早寒武世早期全球性海平面上升时,在区域性深水滞留缺氧的陆棚到斜坡环境沉积的,具有单层厚度大、发育层位多、分布面积广、热演化程度高、后期改造强等特点,构成了中国南方页岩气发育的强大物质基础。以黑色碳质泥质岩类为重点,对其有机碳丰度、可溶沥青丰度与组成、干酪根特征等方面进行了较为系统的有机地球化学分析;结合有机质演化阶段,为页岩气藏的远景评价和地质勘探工作提供参考。

The shale gas enrichment in south China with the favorable geology conditions has the similar conditions of shale gas resource reserves and potential development as the shale gas enrichment of America.The most favorable areas of China are located in Sichuan basin,Micangshan-Dabashan foreland,east part of Chongqing,the northern Guizhou province,Hunan and Hubei provinces and north part of Jiangnan uplift.Black shale is widely distributed in the Cambrian formation.This region was formed in the early Cambrian in which the deposits occurred in the regional deep water to the slope of the continental shelf with stranded anoxic environment when global sea level rose rapidly.In general,it is a region with a large thickness of a single layer,multiple developed layers,a wide distribution area,high thermal maturity,a high degree of later reformation,and so on.These features help this region become the advantage foundation of shale gas in south China.The focuses of this paper are the black carbargilite and the organic geochemistry analysis of organic carbon abundance,soluble bitumen abundance and components,and its kerogen characters.