碳酸盐岩储层缝内暂堵转向压裂实验研究

顺北油气田碳酸盐岩储层非均质性强、连通性差，采用暂堵转向压裂技术可提高裂缝复杂程度，改善开发效果，但碳酸盐岩储层暂堵条件下的裂缝起裂扩展规律尚不明确。为此，采用改进后的三轴压裂物模模拟实验装置，进行了碳酸盐岩暂堵转向压裂实验研究。依次注入压裂液和加有暂堵剂的压裂液，分析了注入暂堵剂前后的施工压力曲线变化情况和暂堵转向压裂后的裂缝形态，从而明确了裂缝暂堵转向规律和实现缝内暂堵转向压裂的条件。研究表明，暂堵可增大裂缝复杂程度；为了实现缝内暂堵转向压裂，岩样内要发育有天然裂缝或层理面，同时暂堵剂能够进入裂缝内并实现封堵，使施工压力升高，从而实现新缝开启或转向。碳酸盐岩缝内暂堵转向规律研究结果为顺北油气田碳酸盐岩储层压裂改造提供了理论依据。 

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.