Sedimentary Characteristics and Model of Permian System in KeBai Area in the Northwestern Margin of Jungar Basin

Key words: 
• Junggar Basin

Abstract: Permian is the important oil layer and reservoir in the northwestern margin of Junggar Basin. By means of observing cores, analyzing sections and well logging data, we studied on the sedimentary environment and characteristics of the Permian glutenite which stored in the downdip block of KeBai fault in the northwestern margin of Junggar Basin. The result shows that some glutenites pertained to alluvial fan deposit, the other pertained to front fan delta deposit. The former was brown, wealthy of argillaceous matrix, poorly rounded and sorted and poor reservoir physical property; the later was poor of argillaceous matrix, Supermature calcitic or zeolitic cementation, well rounded and sorted with good reservoir physical property. So, we have established the combined sedimentation model of alluvial fan and delta fan. This model emphasized the importance of lake strandline and deemphasized the boundary of alluvial fan and delta fan. We summarized the lithologic characteristics and depositional texture and sequence of each subfacies of alluvial fan, and delta fan and provided the ideas of enplorating the Permian high quality reservoirs in the northwestern margin of Junggar Basin. 