Organic geochemical characteristics and significance of Permian Gufeng formation siliceous shale in well CSDP-2 of South Yellow Sea central uplift

In order to understand the hydrocarbon generation potential of the siliceous shale in the Permian Gufeng Formation of the South Yellow Sea, the organic geochemistry and organic petrology of the siliceous shale in the Gufeng Formation of the CSDP-2 well were studied and analyzed. It is found that the TOC of the samples is mainly between 9% and 12%, and T max is mainly distributed between 510 and 540 °C. The value of the organic microscopic type index (TI) is between 25.71 and 31.00, which is a set of II 2 high-quality source rocks with high organic matter abundance in the over mature stage of large-scale gas generation. According to the distribution characteristics of Molecular fossils in siliceous shale of Gufeng Formation of well CSDP-2, bacterial organic matter is the main hydrocarbon generating parent material, and aquatic animal organic matter is an important hydrocarbon generating parent material. The siliceous shale in Gufeng Formation of CSDP-2 well is in the stage of large-scale gas generation; Therefore, the Gufeng Formation in the central uplift of the South Yellow Sea has the material basis for the formation of large-scale shale gas reservoirs. At the same time, the siliceous metasomatism of the siliceous shale reservoir of Gufeng Formation is not conducive to the primary migration of oil, and there is much oil and gas remaining in the reservoir.