低张力聚合物微球调驱机理及注入参数优化

Mechanism of Profile Control and Injection Parameters Optimization of Low Tension Polymer Microspheres

聚合物微球在溶胀以前粒径较小,能随注入水顺利进入油藏深部,在地层高温作用下,聚合物微球吸水溶胀,粒径变大,最后以架桥的方式堵塞地层喉道,实现油藏的深部调剖。在低倍显微镜下观察岩心切面的微球,可以明显看到其运移—架桥—堵塞—变形—突破再运移—再堵塞的调剖过程。宏观机理验证中发现注入聚合物微球后,驱替压力明显上升,证明了堵塞的存在。通过注入参数优选,最后发现0.3%微球和0.5%表面活性剂1∶1在0.5 m L/min速度下交替注入0.5 PV,溶胀48 h后的驱油效果最好。

The polymer microspheres have smaller particle size before swelling, can successfully enter the deep reservoir with the injection of water. In the formation of high temperature, polymer microspheres absorb water to swell, particle size becomes larger, and finally they can plug the roar by bridging way to realize the reservoir deep profile control. Through observation of the microspheres in core sections by low magnification microscope, we can clearly see the transporting-bridging-blocking-deformation-breaking remigration-re-blockage of the profile control process. After the macroscopic mechanism verification, it＇s found that there was a significant increase in the displacement pressure after the injection of polymer microspheres, which proved the existence of the blockage. Through the injection parameters optimization, it＇s finally found that alternate injecting 0.5 PV 0.3% microspheres and 0.5% surfactant（1∶1） at 0.5 mL/min can obtain the best flooding effect after the swelling of 48 h.