Sedimentary Characteristics of Braided River in Small Rift Basin

The microfacies type and sedimentary feature of the braided river were analyzed through the study of braided river sandbody outcrops in the Qianjiadian Jurassic rift basin in Yanqing silicified wood park of north Beijing,starting from the description of lithofacies genetic composition and sedimentary structures.The results indicate that the braided river depositional system includes the multi-floor stacked braided channels and the crevasse or overbank deposits between the channels.The main controlling factors on the distribution of braided river sandbodies are analyzed,the braided channel width/depth empirical formula are derived by using semi-quantitative method based on measured field data.The study provides a basis for analyzing genetic types of braided river reservoirs,their spatial distribution prediction and reservoir modeling.