低矿化度水驱后聚合物驱提高采收率实验

Experimental research on recovery efficiency improved by polymer flooding after low salinity water flooding

周治岳 温中林 杨伟 陈勇全 朱秋琳

中国石油青海油田分公司采气一厂，青海 格尔木 816099

No.1 Natural Gas Plant, Qinghai Oilfield Company, PetroChina, Golmud 816099, China

相较于高矿化度水驱，低矿化度水驱更有利于提高原油的采收率，因此，为了进一步提高三次采油的效果，室内开展了低矿化度水驱后聚合物驱提高采收率的实验研究。考察了不同矿化度水对聚合物黏度和黏弹性的影响，并评价了不同矿化度水驱后聚合物驱的驱油效果。结果表明：在水的矿化度为1 875 mg/L时，聚合物GZ￣2溶液的黏度最大，并且流体具有良好的黏弹性；而随着矿化度的增大，聚合物溶液的黏度逐渐下降，黏弹性逐渐变差。模拟岩心驱油结果表明：使用低矿化度水驱时，原油的采收率明显高于高矿化度水驱；采用低矿化度水驱后聚合物驱的最终采收率能够达到65.4%，比采用高矿化度水驱后聚合物驱最多可提高8.1百分点。这说明将低矿化度水驱和聚合物驱相结合，能够起到良好的协同作用，聚合物在低矿化度水条件下能够发挥更好的驱油效果。

Compared with high salinity water flooding, low salinity water flooding is more conducive to improving oil recovery. Therefore, in order to further improve the effect of tertiary oil recovery, laboratory experiments of polymer flooding after low salinity water flooding were carried out to improve oil recovery. The effects of water with different salinity on polymer viscosity and viscoelasticity were investigated, and the displacement effect of polymer flooding after water flooding with different salinity was evaluated. The results show that when the salinity of water is 1,875 mg/L, the viscosity of polymer GZ-2 solution is the highest, and the fluid has good viscoelastic properties. With the increase of salinity, the viscosity of polymer solution decreases gradually, and the viscoelastic properties become worse. The results of core flooding simulation show that the recovery of crude oil with low salinity water flooding is obviously higher than that with high salinity water flooding. The final recovery of polymer flooding with low salinity water can reach 65.4%, which is 8.1% higher than that of polymer flooding with high salinity water flooding. This shows that the combination of low salinity water flooding and polymer flooding can play a good synergistic role, and polymer flooding can play a better role in low salinity water conditions.

10.6056/dkyqt201906019