注水开发对砂岩储层孔隙结构的影响

以中国东部某油田为例 ,讨论了注水开发对砂岩储层孔隙结构的影响。孔隙结构参数表明 ,注水后砂岩储层的喉道平均直径和喉道直径中值明显增加。孔喉分布的峰态表明 ,由于注水开发的影响 ,喉道的分选程度降低。注水后 ,砂岩储层的退出效率降低 ,最小可流动孔喉直径增大 ,这表示流动主孔喉向大孔喉方向移动 ,而且流动主孔喉控制的孔隙体积也增加了 ,从而导致渗透率提高。注水后砂岩储层的孔隙结构和非均质性均发生了极大的改变。这项研究结果对提高采收率 ,尤其是对制订三次采油方案具有十分重要的意义。

EFFECT OF WATERFLOODING ON PORE STRUCTURE IN SANDSTONE RESERVOIR

With an oilfield example from the Eastern China,this paper discusses changes of pore structure in a sandstone reservoir after waterflooding.The pore structure parameters show that mean and medium diameters of throat in the sandstone reservoir will observably increase after waterflooding,and a kurtosis of throat distribution indicates reduction of throat sorting due to waterflooding.Waterflooding can also make mercury withdrawal efficiency of the sandstone reservoir decrease,and the minimum flowing pore throat diameter increase showing that the main flowing pore throats moves to larger ones and pore volume controlled by them increases,leading to an increase of permeability.In one word,pore structure and heterogeneity in sandstone reservoirs can change remarkably after flooding.This is of great significance for raising oil recovery,especially for making plans for tertiary oil recovery.