Abstract: Taking the sandstone reservoirs in well block Shun 9 in the Tahe Oil Field as an example, the reasonable pressure difference including stress sensitivity in reservoirs with low porosity, low permeability and microfracture is calculated with 3 different methods. The method which is most favorable for the study area is chosen after comparison. The critical pressure difference in well block Shun 9 is calculated as 22.10 MPa. The result is applied in the gas lift depth calculation in Shun 9CH, that is, under 888.53 m.