To address the problems of channeling through existing fractures, uneven reservoir stimulation,and limited recovery enhancement during reservoir development,the parameters of temporary plugging and directional fracturing were optimized through physical simulation experiments, and the fracture propagation laws were systematically analyzed.The effects of the mass ratio between granular temporary plugging agents (particle size: 0.31~0.34 cm) and powdery temporary plugging agents (particle size:0.10~0.18 cm), the total mass of temporary plugging agents,and the fracturing fluid injection rate on the plugging performance were investigated. Combined with large-scale physical simulation experiments, the fracture deflection characteristics were further analyzed. The results indicate a synergistic optimal relationship among the parameters.When the mass ratio of the two agents is 5∶5, the fracturing fluid injection volume is 2 000 mL, the total agent dosage is 50 g, and the injection rate is 100 mL/min,the sealing effect is optimal,with the sealed zone withstanding a stable pressure of 9.54 MPa and forming in just 81 s. In the large-scale physical model, the fracture deflection angle reached a maximum of 167.5° under this parameter combination, effectively blocking the propagation of existing fractures and forcing the fracturing fluid to expand into undeveloped areas of the reservoir. This study clarifies the optimal parameter system and fracture propagation mechanism,providing reliable experimental evidence and theoretical support for the in-situ remediation of existing fractures.

The flow field datributions of the hydrocyclone such as static pressure, tangential velocity and turbulent dissipation rate by loading PBM model and the conventional model, respectively. The results show that the two methods are approximately the same in the prediction of flow field characterics. Therefore, the CFD numerical simulation method based on the PBM model was used to simulate the separation characteristics of the hydrocyclone numerically. And the effects of the factors such as inlet flow rate, overflow split ratio, oil phase viscosity and density on the oil droplet size distribution and oil?water separation characteristics are explored. The results indicate that the separation efficiency of hydrocyclone increases firstly and then decreases with the rising of the inlet flow rate, and reaches a maximum efficiency of 98% as the processing capacity is 4 m³/h; the increase of the overflow split ratio is beneficial to improve separation efficiency; the radial force on the oil droplets decreases with the increasing of the viscosity of the oil phase, preventing aggregation and significantly reducing the separation efficiency as well; the higher density of the oil phase leads to larger the average oil droplet diameter of the tail pipe section and a reduced separation efficiency. Above all, the CFD?PBM numerical simulation method can be used to investigate the particle size distribution and variation characteristics of oil droplets in hydrocyclone, in order to reveal the separation mechanism of the hydrocyclone from different scales.