油层受水敏伤害时水驱油渗流特征

利用真实的砂岩模型进行了单、双及组合模型3种类型的水驱油实验,比较了有水敏、无水敏伤害时水驱油特征的差别,并对两种条件下的驱油效果进行了评价.研究结果表明,有水敏伤害的注入水驱油与无水敏伤害的地层水驱油相比,水驱油的入口压力增高,孔隙结构非均质性加强,水驱油绕流加重,驱油效率及波及系数降低;两种条件下的水驱油方式均为活塞式,残余油类型主要为绕流形成的簇状残余油.影响木钵区块延10油层驱油效率的主要因素是储集岩的孔隙结构非均质性、水敏伤害、注水压力及加压方式.在对木钵区块延10油层注水开发中,应加强对储层非均质性的研究,并注意采取有效的储层保护措施,提高油层采收率.在注水开发过程中,应逐渐提高注水压力,以最大限度地开采木钵延10油层的石油资源.

Seepage flow characters of oil displacement with water drive in water-sensitive formation of Mubo Yan10reservoir

Three kinds of water drive experiments including the single model,double model and the combined natural sandstone micro-model were carried out.The oil displacement characters of water drive reservoir with water-sensititve damage and without water-sensitive damage were compared,and the oil displacement efficiencies of water drive under the above conditions were estimated.Compared with the formation water drive reservoir without water-sensitive damage,the injection pressure of water drive in the water-sensitive damaged formation was raised,and the heterogeneity of pore structure became stronger.The injected water resulted in bigger detours,and the displacement efficiency and the sweep efficiency decreased.The oil displacement ways of water drive were mainly piston-types under the two different conditions, and the types of residual oil were mainly clusters.The heterogeneity of porestructure,water sensitivity,injection pressure and the increasing pattern of injection pressure are the chief factors affecting oil displacement efficiency of water drive in Mubo Yan10 reservoir.It is suggested that the heterogeneity of Mubo Yan10 reservoir should be studied furthermore，and the favorable measures for protecting this reservoir should be adopted in order to enhance oil recovery.The injection pressure should be gradually raised,and the recovery ratio of this reservoir should be enhanced possibly.