Abstract: The detailed description of core from Shinan oilfield in Junggar basin is presented. The study of sedimentary microfacies and facies marker classifications is made by means of sedimentary characteristic of Jurassic Toutunhe formation (J₂t²), integrated with well logs and comprehensive logging data. The results show that the rock type of J₂t² is dominated by lithic sandstone with lower composition maturity, reflecting fast sedimentary velocity and complex parent rock composition. For free bi-element structure, the formation features big width-depth ratio and varied location of channel and river island. Its braided fluvial facies is divided into bed subfacies and flood-plain subfacies followed by such microfacies as channel deposit, river island, natural barrier, bank lakelet, fluvial flooding plain and crevasse splay, including their vertical sedimentary sequence features and distribution.

Key words: Junggar basin, Jurassic, sedimentary facies, sedimentary type, sedimentary characteristic