Sedimentary palaeogeography of the Sinianin Upper Yangtze Region
Liu Jingjiang1, Li Wei1, Zhang Baomin1, Zhou Hui1, Yuan Xiaohong2, Shan Xiuqin1, Zhang Jing1, Deng Shenghui1, Gu Zhidong1, Fan Ru1, Wang Yongjun1, Li Xin1
1 Research Institute of Petroleum Exploration and Development,PetroChina,Beijing 100083
2 Research Institute of Petroleum Exploration and Development,Huabei Oilfield,Renqiu 062550,Hebei
Based on the analysis of wells,loggings,seismic information and other materials of synthetic study,palaeogeography of different formations or members of the Sinian in Upper Yangtze Region was mapped,sedimentation and reservoirs were systematically studied. It indicated that the Upper Yangtze Platform was a semi-platform during the Sinian,and the process of sedimentation could be divided into three stages of pre-platform deposition,carbonate platform deposition and restricted sea basin deposition. The Chuan-Dian great rift adjoining to the western margin of the Upper Yangtze Platform played an important role in the platform evolution,formation of sedimentary palaeogeography framework and facies distribution of the Upper Yangtze Region. During the period of the Upper Sinian Dengying Formation,the Upper Yangtze Platform had ever undergone a fast subsidence caused by rifting,going through an ephemeral change from platform to basin. The evolution of the lithofacies palaeogeography controlled the formation and distribution of reservoirs of the Sinian in Sichuan Basin,and also controlled the formation and distribution of conventional petroleum and shale gas in this region.
