缝洞型油藏不同井间连通模式对调剖的影响

Influence of different interwell connected pattern onprofile control of fractured-cave carbonate reservoir

针对碳酸盐岩缝洞型油藏的井间连通模式,依据储集性宏观上相似、连通关系具有可借鉴性的原则,设计制备裂缝网络和裂缝-溶洞两种简化的缝洞岩心物理模型,通过凝胶调剖实验,研究了不同井间连通模式对调剖的影响。结果表明:两种简化物理模型的含水率变化均表现为经过一段无水采油期后暴性水淹,注凝胶调剖后含水率明显下降,与裂缝-溶洞模型相比,裂缝网络模型含水率下降幅度较大,且后续水驱过程中含水率上升较慢;裂缝网络模型的水驱采收率、最终采收率和采收率提高程度均高于裂缝-溶洞模型;裂缝网络模型注凝胶调整吸水剖面、扩大注入水波及体积的作用更明显,调剖效果更好。

Fractured-cave carbonate reservoir has strong anisotropism, complicated oil-water relationship and flow mechanism. Thus,the application of profile control in these reservoirs is less effective. In this study, we summarized four connecting models. On the basis of macro similarity of the reservoir property and referentiability of the connecting relationship, we designed two simplified physical models of the core, fractured-cave and fractured-net, to investigate the impact of different connecting models on profile control using polymer gel as the profile control agent. The experimental results demonstrate that in the two models, the water-free oil production period was short and the water ratio was close to 100% rapidly after water breakthrough. After profile control, both the water ratios of fractured-cave and fractured-net model were decreased. However, the water cut of fractured-net model was reduced more significantly compared with that of fractured-cave model. The increase of the water ratio for fractured-net model was slower in the subsequent water flooding. The water flooding recovery, ultimate recovery and improved oil recovery degree for the fractured-net model were all higher than those of the fractured-cave model. The role of polymer gel injection in adjusting injection profile and increasing swept volume was more apparent, and the effect of profile control was better.