To delve deeper into the mechanisms of enhancing crude oil recovery through alternating injection-production coupling in complex fault block reservoirs, we established a three-dimensional geological model specific to the characteristics of the Paleogene oil-bearing strata in the Biyang Depression. The model’s accuracy was rigorously validated by integrating actual sandstone-mudstone facies, physical property parameters, and discretized simulation values. Based on the finite element difference method and leveraging the tNavigator software, we conducted layered streamline numerical simulations on the fault block reservoir model. This approach allowed us to clarify the injection-production correspondence and characterize the distribution of residual oil. By establishing a mechanistic model, we analyzed the impact of various factors on fluid production characteristics, pressure, and water cut, and revealing the mechanisms of injection-production coupling enhances oil recovery. The results indicate that the formation pressure and advantage seepage channels exert a significant influence on the injection-production correspondence. And the injection-production coupling technology can expand the swept volume of injected water. Among the four primary types of residual oil, the retention in interwell type of the residual oil accounts for the highest proportion (52.7%), totaling 38.45 × 104 t. Enrichment in low-permeability area and well pattern uncontrolled types of residual oil accounted for 19.59% and 19.08%, respectively. In contrast, the residual oil associated with weak-match between injection and production comprises only 7.14%. The intervention timing of intervention emerges as a crucial factor in injection-production coupling. Specifically, higher pressure maintenance levels lead to lower water cuts and subsequently better outcomes from injection-production coupling. The periodic injection-production ratio should be maintained at 1:1.