新型聚合物复合纳米微球调剖驱油剂研究

Study on a New Polymer Composite Nano‐Microsphere for Profile Control and Oil Displacement

针对大庆油田某区块油井含水率高、水窜现象严重、水驱开发效果差等特点,采用分散聚合法研制了一种新型聚合物复合纳米微球调剖驱油剂NWQ‐2,并在室内评价了其粒径分布、吸水膨胀性能、耐温抗盐性能、黏弹性能、调剖封堵性能以及驱油性能。结果表明,复合纳米微球NWQ‐2的平均粒径为512.6 nm,且粒径分布均匀,在蒸馏水中20 h的吸水膨胀倍数可以达到10倍以上,在高温(120℃)高矿化度水(75200 mg/L)中20 h的吸水膨胀倍数仍能达到8倍以上,说明NWQ‐2具有良好的吸水膨胀性能和耐温抗盐性能;复合纳米微球NWQ‐2吸水膨胀后具有良好的黏弹性能,对不同渗透率的岩心均具有良好的调剖封堵效果,能使大孔道得到有效封堵,增大注入压力,使后续注入流体更多的进入微小孔道;非均质岩心中注入0.5 PV复合纳米微球NWQ‐2后,能显著提高岩心水驱后的采收率,增幅可达20%以上,具有良好的驱油效果。

According to the characteristics of high water cut,serious water channeling and poor water drive development in a block of Daqing Oilfield,a new polymer composite nano‐microsphere profile control and oil displacement agent NWQ‐2 was developed by dispersion polymerization method,and its particle size distribution,water absorption and expansion performance,temperature and salt resistance performance,viscoelastic performance,profile control and plugging performance and oil displacement performance were evaluated in the laboratory.The results show that the average particle size of NWQ‐2 is 512.6 nm,and the particle size distribution is uniform.The water absorption expansion ratio in distilled water for 20 h can be more than 10 times,and that in high temperature(120℃)and high salinity water(75200 mg/L)for 20 h can still be more than 8 times,which shows that NWQ‐2 has good water absorption expansion performance,temperature resistance and salt resistance.After water absorption and expansion,it has good viscoelasticity,good profile control and plugging effect for cores with different permeability,which can effectively block large channels,increase injection pressure,and make the subsequent injected fluid enter more micro channels.After injection of 0.5 PV composite nano microsphere NWQ‐2 into heterogeneous core,the recovery of core after water flooding can be significantly increased by more than 20%,which has good oil displacement effect.