In order to determine the technical and economic boundaries of well pattern adjustment，technical and economic boundaries of well spacing，longitudinal permeability variation coefficient，and thickness and span of layer series combination were studied through dynamic analysis，theoretical calculation，numerical simulation and economic evaluation. The variation waterflood controlling level with well spacing was studied through dynamic analysis. Relationship between recovery efficiency and well spacing was studied using numerical simulation to determine rational well spacing. Limit of permeability variation coefficient was obtained by conceptual model. Rational combination thickness of layer series with different well spacings and oil prices was calculated based on profit and loss balance principle using economic evaluation method.Combination series span was determined through theoretical calculation based on well spacing and combination thickness of layer series. Initial oil rate and water cut after adjustment was calculated using numerical simulation and economic evaluation. Reasonable well spacing of Lazhong block is 150 m，and reasonable combination thickness is 7.5 m. The combination span is 50 m，and the longitudinal permeability variation coefficient is 0.7.