Abstract: In view of the problems such as accelerated decline, intensified gas channeling, and difficult lifting caused by insufficient formation energy in the middle and late stages of natural energy development in gas-cap and edge-water reservoirs, a three-dimensional well pattern for energy replenishment was constructed through converting gas production wells at high positions to gas injection, conducting peripheral water injection from wastewater reinjection wells at low positions, and converting oil wells within the oil ring to water injection. Mechanistically, converting oil wells to water injection expands the sweep coefficient of water flooding, mobilizes the remaining oil stagnated between wells, and reduces water cut; the synergistic effect of gas-cap injection and peripheral water injection maintains the dynamic balance of the oil-gas interface and oil-water interface, increases the displacement multiples of gas flooding and water flooding, and thereby enhances crude oil recovery. The research on streamline models indicates that this three-dimensional well pattern can better achieve multi-directional balanced displacement according to the characteristics of gas-cap and edge-water reservoirs. On this basis, by coupling the characteristic curves of gas flooding and water flooding, an injection allocation formula for balanced displacement of gas injection and water injection is established, and the injection allocation parameters are finally determined combined with reservoir numerical simulation. In the field test, the test well group effectively achieved the goals of reducing the gas-oil ratio, lowering the water cut, and increasing the liquid production and oil production. The deployment of the three-dimensional well pattern aiming at balanced displacement and the calculation method of injection allocation for different displacement media provide references for the injection and production optimization of similar reservoirs.