Abstract: Taking the super heterogeneous heavy oil reservoir of Jurassic Qigu formation in Fengcheng oilfield and using indoor rock mechanics experimental results, the paper establishes numerical models of coupled stress field, carries out numerical simulation analysis on SAGD fast start-up expansion process, and describes expansion features for the super heavy oil reservoirs. The results show that when the fast start-up ends, the porosity and the permeability in near-wellbore zones increase by 2% and 10%~100%, respectively, and the volume expansion rate can reach 1.74%, indicating the reservoir can be effectively expanded. Based on which, the influences of horizontal well trajectory, reservoir lithology and physical property on the fast start-up technology are studied, and the limits of SAGD rapid and uniform start-up technology are obtained. The study results reveal that the well groups with the following conditions can satisfy the fast start-up technology: no large mudstone section is developed along the horizontal section, the order differential of the permeability in the horizontal section is less than 3 and the vertical deviations between the upper and lower trajectory in the SAGD well are less than 1 m or the horizontal deviation is less than 2 m. The fast start-up technology should be implemented according to the actual situations of SAGD well groups and reservoirs during field practices