Abstract: Upper Permian and Lower Triassic in northwestern margin of Junggar basin are important oil productive zones, with sedimentary facies dominated by alluvial fan.As the traditional saying goes “where there is alluvial fan, there is oil or gas”, it is therefore essential to predict the distribution of alluvial fan.The alluvial fan in this area can be classified into fault-cliff fan and talus fan.In accordance with their characteristics, seismic stratigraphy was successfully used to predict i t in recent years, which included the study of the distribution of fault line and pinchout line, seismic facies analysis, interval velocity analysis, quantitative analysis of property, well constrained inversion and interpretation. Six alluvial fans and their facies belt distribution were proved, ten appraised well location were determined, and the commercial oil flow has been obtained in seven appraised wells at present.

Key words: Junggar basin, Alluvial fan, Lateral, Prediction, Seismic stratigraphy, Seismic facies, Interval velocity, Inversion