纵向非均质储层凝胶调剖剩余油分布特征实验研究

Experimental study on distribution characteristics of remaining oil in vertical heterogeneous reservoirs by gel profile control

设计、制作了带有饱和度场监测的含电极两层纵向非均质平板岩心模型,通过电阻率法实现对非均质模型中剩余油分布定量描述,通过模拟正韵律厚油层水驱、聚合物驱、凝胶调剖实验,测试调剖前后剩余油分布,得出不同注入方案、不同驱替阶段下模型内调剖驱替效果及剩余油分布特征。实验结果表明,渗透率级差越大,低渗透层内剩余油越富集,调剖后波及程度提高幅度越大,高渗透层水流优势通道越明显,波及程度越大、洗油效果越好;不同注水量对低渗透层的波及效果没有明显改善,不同方案开发效果基本一致;聚合物注入量越小,调剖时机越早,提高采收率幅度越大;调剖剂用量越大,对高渗透层的封堵半径越大,低渗透层的波及体积大幅度提高,剩余油动用程度越高,油水前缘向生产井推进越远。

A double-layer vertical heterogeneous plate model of core that can monitor saturation field was designed and fab⁃ricated.The remaining oil distribution in the model was quantitatively described with the resistivity method.Through simu⁃lation of the water flooding,polymer flooding,and gel profile control experiments of thick positive-rhythm oil layers,the re⁃maining oil distribution before and after gel profile control was tested,and the displacement efficiency and remaining oil distribution characteristics of the profile control of models in different injection schemes and displacement stages were ob⁃tained.According to the experimental results,the larger permeability ratio led to the more rich remaining oil and the bigger increase in swept volume in low-permeability layer after profile control.A greater permeability ratio also resulted in the more evident preferential migration passage of water flow in the high-permeability layer,larger swept volume,and better displacement efficiency.The different water injection volumes received almost the same development effects with little im⁃provement on swept volume in the low-permeability layer.A smaller polymer injection volume and earlier profile control brought about higher enhanced oil recovery(EOR).The more profile control agent led to larger plugging radius of the highpermeability layer,more increment of swept volume in the low-permeability layer,more percentage of producing remaining oil,and longer distance that the oil-water front advances to the production well.