中低渗油藏调驱用纳米聚合物微球的稳定性能评价

The Stability Assessment of Nano-scale Polymer Particles in Medium-Low Permeability Reservior For Profile Modification

本文针对纳米微球调剖的要求,通过分散稳定实验和粒径的电镜分析对三种反相微乳液制备的微球进行了筛选,并对选定的MG-50型微球进行热稳定性实验和剪切稳定性实验。结果表明,MG-50型微球在地层水和注入水中长期分散稳定,22 d粒径膨胀倍数高达7倍,分布范围大;0.3%MG-50微球乳液注入低渗透填砂管在85℃放置三个月后的封堵率仍在75%以上,但是强度下降,易破碎;流变性测量表明该乳液剪切变稀,结合Darcy公式和Poiseuille定律计算了体系不同速率下注入低渗岩心的剪切速率,结果显示剪切速率对的阻力系数影响不大,即该体系有较好的抗剪切作用。

The stability of nano-scale polymer particles is the key factor on its application. In view of the requirements of nano-sclale polymer particles applied in profile modification, the desired nano-particles coded MG-50 with initial state of reverse microemulsion was selected from three like products according to the performance of dispersion stability tests and radius analysis by scanning electron telescope, and then was testified by thermal resistance and shear stability. The results showed that MG-50 exhibited great stability both in formation water and in injection water with 7 times of initial radius and wide distribution range in 22 days. And MG-50 with 0.3% mass fraction had a plugging efficiency more than 75% in low permeability sandpack after aging for 3 month at 85~C ; nevertheless, it became fragile and less rigid. In addition, though 0.3% MG-50 solution was shear thinning emulsion, it was evident that shear velocity calculated with evolution of injection velocity by combination of Darcy Law and Poiseuille Law in medium-low permeability core had a little effect on residual resistence factor, indicating good performance of shear resistence.