海上油藏变浓度聚合物驱剖面控制实验与应用

针对渤海强非均质、中高粘油藏聚驱过程中低渗层吸液剖面初期改善,之后又变差的现象,首先通过岩心驱替实验分析了聚合物溶液浓度对吸液剖面的影响规律;然后测试了高浓-低浓聚合物驱交替注入方式在非均质油藏中的驱油效果。结果表明:通过在聚驱早、中期阶段增加聚合物溶液的浓度,能够对高渗层有效的封堵,增加注入压力、显著改善低渗层的吸液剖面。结合油田实例研究表明:在现场条件允许情况下,相同聚合物用量,采用高浓-低浓段塞聚合物驱方式相比恒浓度聚驱,能够提高低渗层动用程度,增加总体采收率约1%。

Experiments and Application of Variable-concentration Polymer Flooding for Offshore Reservoirs

Variable-concentration polymer flooding core experiments were conducted on injection profile performance during polymer flooding according offshore heterogonous formations and higher oil viscosity. The flooding methods using the same polymer injection with different concentration were investigated to control the injection profile, which showed that higher concentration solution slug injection in earlier period could block the higher permeability layers effectively, and improve the injection profile and flooding efficiency in tight layers.The reservoir simulation results of field A also showed that the high-low concentration slug combination polymer flooding design could give the highest recovery with the same polymer consumption.