上扬子地区震旦纪沉积古地理

Sedimentary palaeogeography of the Sinian in Upper Yangtze Region

通过整理大量的钻井、测井、地震和其他综合研究资料,系统编制了上扬子地区震旦系各层段的岩相古地理图,进行了较为系统的沉积储集层研究。该研究显示震旦纪上扬子台地是一个半孤立的台地。震旦系沉积可以划分为前台地沉积、碳酸盐岩台地沉积和局限海盆沉积。紧邻上扬子台地西部边缘发育的川滇大裂谷对上扬子台地的演化、沉积古地理格局的形成及沉积相带的展布有着重要影响。灯影期,上扬子台地曾经有过一次由裂谷活动导致的快速沉降,经历了一次短暂的由台地到海盆的变化。岩相古地理的演变控制着四川盆地震旦系沉积储集层的形成与分布,也控制着该区常规油气及页岩气的形成与分布。

Based on the analysis of wells, loggings, seismic information and other materials of syn- thetic 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 impor- tant role in the platform evolution, formation of sedimentary palaeogeography framework and facies distri- bution of the Upper Yangtze Region. During the period of the Upper Sinian Dengying Formation, the Up- per 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.