After 36 years of waterflood development, the Es3 reservoir of Jin45 fault block has reached high water cut development stage. The water cut rate exceeds 90% and case pipe breakdown rate exceeds 80%. In the past 20 years, the reservoir has been in development status of low well opening rate and low oil production rate. In recent years, the geological reserves of Es2 reservoir have been confirmed to be large-scale through the overall reevaluation, which has the geological condition for using a set of strata for development. In order to improve current development status of Jin45 fault block, the Es2 reservoir will be put into production, which is located above Es3 reservoir. In this study, according to the oil layer allocation of Es2 reservoir and the residual oil allocation of Es3 reservoir, the well pattern of “straight well combined horizontal well” is deployed in Es2 reservoir, some old wells in the core area are returned to Es2 reservoir, and the new drilling wells taking Es3 reservoir into account. At the same time, according to the sedimentary microfacies and residual oil allocation in Es3 reservoir, the original three sets of layer system “adjacent combination” are broken, and two sets of high permeability and low permeability layer system are regrouped according to the principle of reservoir quality “similar combination”. On the basis of layer system recombination of Es3 reservoir and well network deployment of Es2 reservoir, the injection-production pattern of old and new layer system is comprehensively considered and adjusted. After the well network reconstruction, the perfect injection-production pattern is formed for each layer system. By regrouping the layer system and adjusting the well network of each layer system, the water flood development effect of old oilfield is effectively improved and the water flood recovery efficiency is increased. The successful experience of the secondary development of Jin45 fault block has good reference for the development of similar reservoirs.