Sedimentary Facies And Paleogeographic Evolution Of Huizhou Depression, Zhujiang Basin In Neogene

Zhujiang basin is one of the most potential oil reservoir region in China, and Huizhou depression is the important exploration horizon. The reservoir is dominated by burial depth, sedimentary facies,rock structure and diagenesis, its oil storage ability and produces can exist the huge difference. Therefore, investigating the sedimentary facies, the spreading characteristic of facies zone and the relations of them to the oil layer disposition, the sandstone body type and the space-time distribution rule has very importance to Zhujiangkou basin oil field for further exploration and the development.On the basis of lots of forerunners data and my research in this thesis, Combining drilling data with observation and analysis of the well core, Enping formation and Zhuhai Formation can be divided into five kind of sedimentary systems such as fluvial-dominated delta ,fan delta, river, shallow lake and beach-barrier by using sedimentary facies signs which is rock feature, sedimentary structure, well log and section texture, Each of the sedimentary systems was subdivided into several subfacies and microfacies, which were described and generalized in detail. At last, I concluded that the Huizhou depression of Zhujiang basin mainly developed river, shallow lake and fan delta sedimentary systems in Enping formation and mainly developed fluvial-dominated delta and beach barrier delta sedimentary systems in the Zhuhai formation. On the basis of the analysis above, I deduce two sedimentary models of the Huizhou depression in the Enping and Zhuhai formation in Neogene.On basis of structure-sedimentation evolution and distribution of sedimentary facies in the Huizhou depression of Zhujiang basin, combined with the sandstone clastic particle types, light and heavy minerals combination, cathodeluminescence feature of quartz and feldspar, and lith-facies, Enping and Zhuhai formation's palaeogeographic pattern are analysed. It shows that the Basin in Enping formation was origined in north and south promontory and Zhuhai formation was primarily origined in north promontory.According to the forerunners data, combining the investigation of sedimentaty system and the source of the sandstone bodies, lithofacies paleogeography characters in Neogene were restored by upbuiding sequence-based lithofacies-paleogeography map working out. In the end, I expound the plane-topology rule of sedimentary facies in the different period and the planimetric distribution of the good reservoir sandstone, and point out the favorable accumulation area belt.