Abstract: Xushen gas field is an ultra-low permeable gas reservoir,with complex geological conditions.In order to understand its reservoir type and boundary conditions,by applying Saphir well test interpretation software to carry out pressure restore well test interpretation of gas wells and test interpretation of the effluent gas well.The results show that the Xushen gas reservoir model mainly has three types,namely closed-type,compound-type and banding-type,and the heterogeneity is serious.For the effluent gas well,when the producing layers emerge water,the permeability generally declined,and reservoir physical property can be affected.