Abstract: In Qiaokou inhomogeneous complex fault block oil- field, interlayer heterogeneity is strong; interlayer interfer- ence is serious ; large differences exist between producing reserves of waterflooding in each layer;and residual oil po- tential is large.Interlayer production replacement is realized through oil well water plugging, separated layer water- flooding and enhanced water injection technologies on base of fine geological research and technology study. Oil layers of type Ⅱ and Ⅲ are put into production to replace layers of type Ⅰ.