流变学法研究交联聚合物凝胶的抗剪切性能

Rheological Studies on Shear-resistant Properties of Crosslinking Polymer Gel

采用控制应力流变仪研究了交联聚合物凝胶的屈服应力与凝胶强度的关系,并考察了凝胶的抗剪切性能,尤其是与油藏渗流速度相当的剪切速率下的凝胶的粘度保持率。结果表明,当聚合物质量浓度为2 g/L时,体系表现为牛顿流体,当聚合物质量浓度为3和4 g/L时,凝胶体系是塑性流体,其屈服应力τy分别为12和28 Pa;与油藏渗流速度相当的剪切速率下,聚合物质量浓度为4 g/L时形成的凝胶粘度保留值大于其它2个体系。交联剂浓度分别为0.25、0.5、1.0和1.5 mmol/L时,凝胶体系的τy分别为6.0、20.0、12.0和2.0 Pa。pH值为4.86的体系表现为牛顿流体,不能形成有效的凝胶;pH值为5.60和6.46的凝胶体系的屈服值分别为12和7 Pa。并且结构强度较高的凝胶在受剪切作用时,粘度保留值较高,即抗剪切性能较好。

The yield stress and shear-resistant properties of crosslinking polymer gel were studied by rheological measurement. It was found that when the concentration of polymer was 2 g/L, the system showed Newton＇s fluid ; when the concentration of polymer was 3 or 4 g/L, the system showed plastic fluid, and the yield stress was 12 or 28 Pa, respectively. The retention value of viscosity of 4 g/L HPAM system was more than those of other systems. When the concentrations of the crosslinking agents were 0. 25, 0. 5, 1.0 and 1.5 mmol/L, respectively, the yield stresses were 6. 0, 20. 0, 12.0 and 2. 0 Pa, respectively. When the pH value of the system was 4.86, the system showed Newton＇s fluid ; when the pH values of the system were 5.60 and 6. 46, the system showed Newton＇s fluid and the yield stresses were 12 and 7 Pa respectively. The strong gels exhibit higher viscosity retention, i.e. higher shear-resistant properties.