Optimizing the displacement of temporary plugging and diversion fracturing of the carbonate reservoirs in Tahe Oilfield

The temporary plugging and diversion fracturing of carbonate reservoirs in Tahe Oilfield is successful, but the displacement parameters in the process of construction have no support of calculation data, which is not beneficial to the popularization and application of temporary plugging and diversion multiple fracturing. The optimization design model of the displacement of temporary plugging and diversion fracturing was established by means of the numerical iterative process based on the fracture geometry model. Then, the optimal displacements in the temporary plugging stage and the fracturing stage of carbonate reservoir were determined. Finally, the construction method of temporary plugging and diversion was developed, i.e., injecting temporary plugging agent at low displacement to plug the tip and injecting fracturing fluid at high displacement to realize diversion. It is indicated that the displacement shall meet the need of diversion pressure and fracture length simultaneously. In addition, as the time goes, the fracture propagation length contributed by the displacement cannot meet the needed fracture length of temporary plugging agent. Temporary plugging agent cannot exert diversion effect no matter how much it is. The displacement optimization under the field conditions by the optimization design model shows that the displacement shall be controlled lower than 3.0 m³/min in the stage of temporary plugging and higher than 6.0 m³/min in the stage of fracturing, which is the most suitable for diversion fracturing. The research results provide theoretical support the field application.