Optimization of refracturing timing in tight oil reservoirs based on an oil water two phase flow model

Repeated hydraulic fracturing is essential for sustaining production in tight oil reservoirs due to rapid post-stimulation decline rates, yet optimizing its timing remains challenging. This study develops a two-phase (oil-water) flow model using finite difference methods to simulate fracture-porous media. The governing equations are solved with the IMPES approach to predict flow and production. Validated with Well X data, the model closely matches actual trends (3.1% deviation in reservoir pressure). Comparing initial and repeated fracturing geometries reveals key production mechanisms: high-permeability fractures increase from 14 to 21 (33% density rise), boosting oil output but accelerating pressure depletion and shortening steady flow periods. Early re-fracturing maximizes cumulative output: simulations show re-stimulation at four years extends production by 18% versus delayed interventions. Gradual pressure decline requires proactive planning to avoid productivity loss. Field validation confirms the model's accuracy, with repeated fracturing boosting oil production by 26% over five years. Results highlight the need to balance fracture-network expansion with pressure maintenance. The proposed two-phase flow model offers a transferable methodology for optimizing re-stimulation schedules based on reservoir dynamics. This work enhances recovery strategies in heterogeneous tight oil systems by linking fracture evolution and flow behavior.