Experimental Study on Temporary Fracture Plugging and Diverting Fracturing of Carbonate Reservoirs

Carbonate reservoirs in Shunbei Oil and Gas Field are characterized by strong heterogeneity and poor connectivity.Although temporary fracture plugging and diverting fracturing can improve fracture complexity and reservoir development, fracture initiation and propagation law in such reservoirs are still not fully understood under the condition of temporary plugging. Therefore, the experimental study on temporary fracture plugging and diverting fracturing of carbonate reservoirs was carried out using the improved true triaxial fracturing experimental system. Fracturing fluid without and with temporary plugging agent were injected in sequence. The change of pressure before and after the injection of temporary plugging agent and the fracture morphology after temporary plugging and diverting fracturing were analyzed, based on which the law of fracture temporary fracture plugging and diverting was clarified. The research showed that temporary plugging can increase the complexity of fracture, and to achieve temporary plugging and diverting fracturing, natural fractures or beddings should be developed in rock so that the plugging agent could enter the fracture and achieve plugging, and so as to realize new fractures opening or diverting with increasing pressure. The research results of the law of temporary plugging and diverting in carbonate fractures would provide a theoretical basis for fracturing of carbonate reservoirs in Shunbei Oil and Gas Field.