三元复合体系的粘弹效应对驱油效率的影响

Influence of viscoelastic effect in ternary combination system on oil displacement efficiency.

针对大庆油田三元复合驱矿场因高浓度碱剂而造成的井筒结垢、卡泵等问题 ,系统地研究了复合体系的流变行为 ,确定了碱剂对三元复合体系粘弹性的影响 ;并在宏观非均质模型、天然岩心以及微观物理模型上进行了对比实验。实验结果表明 ,作为影响驱油效率的因素 ,粘弹效应比超低界面张力更有意义 ;适当降低复合体系的碱剂用量 (界面张力应降至 10 -2 mN/m数量级 ) ,并未明显影响驱油效率。文章首次提出了低碱复合驱的概念 ,否定了超低界面张力在复合驱中的必要性 ,为解决三元复合驱中的碱垢问题探索了新思路 。

Rheological behavior of ASP combination system is studied systematically for scale buildup in wellbore and pump block?up caused by high?concentration alkaline agent in the fields of Daqing oilfield. Influence of the alkaline agent on viscoelasticity of ASP combination system is determined. Project comparative tests are made on macroscopic heterogeneity model, natural core and microscopic physical model. The result shows that as the influence factors of oil displacement efficiency viscoelastic effect has more significance than super low interfacial tension; reducing volume of alkaline agent in the combination system properly (interfacial tension should reduce to 0.01mN/m) has not influenced oil displacement efficiency obviously. The concept of low?alkaline combination flooding is put forward firstly in this paper and the necessity of super low interfacial tension in the combination flooding is negated. A new thinking to solve the problem of alkaline scale in ASP combination system is found. The limit of capillary criterion theory in the application of the combination flooding is discussed.