In the late development stage of waterflooding oilfields, two main challenges arise after entering the ultra-high water cut stage. One is the uneven oil displacement. This can lead to highly scattered remaining oil distribution. The other challenge is the severe ineffective circulation of injected water caused by directional injection-production flow fields. To address these issues, this study focuses on adjusting and optimizing the injection-production flow fields during the ultra-high water cut stage to enhance the utilization of remaining oil. D oilfield is characterized by strong natural edge-bottom water energy. Now, it has entered the ultra-high water cut stage after over 40 years of combined natural and artificial waterflooding. Its comprehensive water cut has already exceeded 97%. Using numerical simulation method combined with analysis of water absorption profiles and other testing data, the remaining oil distribution characteristics of D oilfield are identified. Subsequently, the typical well group rich in remaining oil are selected for flow field adjustment and optimization, so that the schemes of conversion to injection and liquid increasing are proposed. The simulation results show that the remaining oil is primarily concentrated in the northern area. In the profile, the bottom reservoir has severe waterflooding degree, so the remaining oil is rich at the top. For typical potential well group, four adjustment schemes are designed. The case involving converting Well D27 to injection while increasing liquid production rate of Well D69 and Well D78 shows the best oil-increasing effect. it’s estimated that the cumulative oil incremental will reach 3.2 million barrels at the end of the contract period. After the adjustment, localized stream flow redirection is achieved, improving the utilization of remaining oil in the plane. Based on these findings, specific injection-production adjustment suggestions are proposed for D oilfield, which also provide references for similar waterflooding oilfields.