聚合物溶液在地层渗流过程中黏弹性变化规律研究

A Study on Polymer Solution in Seepage Flow in the Formation Process of Viscoelastic Changes

研究了聚合物溶液在多孔介质中的流变特征。分析了聚合物溶液渗流过程中的弹性变化及其影响因素。结果表明,聚合物溶液的黏度在近井地带下降较大,随着推进距离的增加,降解率逐渐减小,保持较高的工作黏度;聚合物溶液在渗流过程中,弹性的变化分为两个阶段:解缠时产生的弹性和拉伸时产生的弹性。相同黏度聚合物溶液,低分子量聚合物溶液,因为浓度较高,分子链间的缠绕度大,解缠弹性较大。解缠弹性和拉伸弹性都改变井底压力梯度,提高驱油效率。

The rheological characteristics of polymer solution in porous medium is studied, analyzed the flexible change and the influence factors on percolation of polymer solution. The results show that the viscosity of polymer degradation near borehole zones gets a larger drop. With the propulsion distance increasing, the degradation be- came smaller, and kept a higher working viscosity. In the process of percolation of polymer solution, the flexible change became two stages： flexible in unwrapping or drawing. Under the same viscosity of polymer solution, the flexible in unwrapping is higher in low-molecular weight polymer solution. The reason is that the concentration is higher and the winding degree between molecular chains is bigger. Both the flexible in unwrapping or drawing can change the pressure gradient and improve oil displacement efficiency.