Fracturing flooding is a new technology that combines traditional conventional water drive, chemical drive, and hydraulic fracturing technologies and injects water under proximity fracture pressure to increase the wave area. It is currently applied in onshore low-permeability oilfields with good results, but the research on the design method of fracturing flooding in offshore low-permeability reservoirs is still lacking. Numerical simulation studies of well fracturing flooding are needed to optimize the key parameters of fracturing flooding development. This study simulates the real-time fracture dynamic expansion process of micro-level fracture expansion for hydraulic fracturing, combines it with a numerical simulation of well pressure-driving, and finally optimizes the parameters of hydraulic flooding. By studying the fracture expansion law, this study determined that the total amount of injection volume had a large influence on both fracture half-length and inflow capacity; the larger the injection rate, the larger the fracture half-length, but the inflow capacity was basically unchanged. It was also found that multiple rounds of fracturing flooding had no effect on fracture morphology or length. In studying the key fracturing flooding parameters in oil wells, it was concluded that the higher the total injection amount, the higher the oil increase in fracturing flooding and the wider the wave area of pressure-driving. Moreover, the higher the displacement, the higher the pressure near the bottom of the well, but there was little difference in the spreading area; in addition, the longer the well shut-in time, the higher the early oil production. Finally, these results were combined with the fracture expansion mechanism model and A21 well model, and the analysis of fracturing flooding parameters based on the simulation results allowed for the following recommendations to be made: the total amount of fracturing flooding injection should be 15,000 m³, the injection rate should be 6 m³/min, the simmering time should be 3–7 days, and only one round of fracturing flooding is required. The mechanism of fracture expansion revealed in this paper can guide the design of fracturing flooding programs in the process of reservoir fracturing flooding development, which is of some significance to the development of the fracturing flooding of offshore reservoirs with low permeability.

The Shunbei 42X well group belongs to fractured-vuggy carbonate condensate gas reservoirs. This type of reservoir exhibits extreme heterogeneity, differing significantly from conventional reservoirs and posing considerable challenges for exploitation. Research on fractured-vuggy carbonate condensate gas reservoirs can begin with modeling and numerical simulation. By using historical data fitting to refine parameters such as pressure, production, and reserves, we can deepen our understanding of the reservoir and the movement patterns of water and oil. Combined with a geological and reservoir engineering analysis of residual oil distribution, this approach enables the evaluation of steady-state production technology feasibility. This study employs numerical simulation to conduct single-well injection production modeling for well SHB42X. First, a numerical model was created in simulation software, defining parameters such as grid spatial location and reservoir temperature. Second, the numerical model was established, and historical production dynamics were fitted using the software’s PVT module. Finally, after successful fitting, subsequent production parameters were set. By summarizing previous studies on gas injection huff-and-puff mechanisms and analyzing changes in parameters like recovery rates after actual injection, the simulation results for natural gas, nitrogen, water, and depleted reservoir development were compared. Further comparisons are made on the throughput effects of nitrogen under varying injection rates, production rates, injection volumes, and well-killing durations. Optimal parameters are selected to provide reference for enhancing subsequent development efficiency.