利用聚合物粘弹效应提高驱油效率

本文研究了孔隙介质中聚合物的粘弹效应及利用粘弹效应提高聚合物驱油效率的可能性。根据粘弹效应系数Rve的定义，通过测定有滞留分子存在的岩心中，不同注水速度下的Rve值，可以判断聚合物溶液在孔隙介质中的流变特征。当Rve=1时，表明聚合物溶液以该流速通过孔隙介质未产生拉伸流动，当Rve＞1时，表明聚合物溶液以该流速流动时产生了拉伸流动；本文系统测试了在一定岩心中Rve与流速的关系曲线，找出了聚合物溶液开始产生拉伸流动的速度──临界粘弹流速Vc1。在此基础上进一步研究了Vc1对聚合物驱油效率的影响，认为聚合物驱的速度必须大于Vc1，才能发挥粘弹性的作用，提高注聚效果。

Utilizing Viscoelastic Effect to Enhance Polymer Displacement Efficiency

Viscoelastic effect of polymer in porous media and the possibility of enhancing polymer displacement efficiency by viscoelastic effect are studied in this paper. Based on the definition of viscoelastic effect coefficient Rre,the rheological behavicor of polymer in porous media can be judged by testing Rre of retained molecules existing in the core under varying velocity of flow.If Rre=1, it shows that polymer solution does not produce strain flow in porous media at this velocity;If Rre>1,it shows that polymer solution produces strain flow. In this paper, the curves of Rre with flow velocity in certain core are tested and critical viscoelastic flow velocity vc1 at which polymer begin to produce strain flow is found. On this base, the effect of vc1 on polymer displacement efficiency is investigated and the conclusion is obtained that the injection rate of polymer must be above vc1 to give play to viscoelastic effect to improve effect of polymer flooding.