The Fang 2 block in the peripheral Songfangtun oilfield has entered a high water-cut development stage，presenting challenges including ineffective water flooding control，a high proportion of low-production wells，and numerous long-term shut-in wells. The conventional inverted nine-spot well pattern configuration can no longer meet the requirements of current efficient exploitation. To address these issues and enhance block recovery efficiency，a“secondary-tertiary combination”development model was adopted，incorporating middle-phase microemulsion flooding technology along with laboratory experiments and reservoir numerical simulation to propose a new development plan. The results showed that when using the compound surfactant system of sodium dodecylbenzene sulfonate and coco-fatty acid ester polyoxyethylene betaine（mass ratio 1∶3）as the core surfactant for middle-phase microemulsion，the system achieved optimal performance with 0.5% dosage of compound surfactant. The optimum mass fraction of n-butanol as cosurfactant was 9.4% determined by alcohol scanning method，and then the optimized salinity value was 4.3% NaCl. In the sand-packed model oil displacement experiment，the injection of middle-phase microemulsion increased the recovery rate by 24.65 percentage points. Furthermore，the existing well pattern was optimized to a five-spot configuration，and then the well spacing adjusted to 195.1 m. After combining secondary water flooding well pattern intensification with tertiary recovery and through CMG numerical simulation prediction，the middle-phase microemulsion injection at 86% water cut could enhance recovery by 20.42 percentage points. The cumulative incremental oil production projected to reach 319 300 t. The research results not only provided effective technical solutions for the development of Fang 2 block in Songfangtun’s peripheral oilfield，but also offered theoretical foundations and practical references for developing other continental low-permeability reservoirs.