疏水缔合聚合物溶液粘弹性及流变性研究

Viscoelasticity and rheological behaviors of hydrophobic association polymer solution

实验测定了缔合聚合物溶液的动态粘弹性、流变性以及在多孔介质中的流变特性。动态粘弹性实验结果表明,在聚合物溶液浓度大于临界缔合浓度时,溶液的弹性模数G′和耗能模数G″明显大于聚合物溶液浓度低于临界缔合浓度时的G′和G″,且存在着一个临界聚合物浓度。低于该浓度时,溶液的G″大于G′,而高于该浓度时,G′大于G″,不同浓度下的G″和G′基本不受剪切应力的影响。在实验剪切速率内,缔合聚合物溶液的宏观流变特征表现为剪切稀释性和剪切增稠性。而在多孔介质中,在低剪切速率下,溶液表现出牛顿流体的特征;随着剪切速率的增加,溶液表现出剪切稀释性和剪切增稠性的流变规律。在进行缔合聚合物驱油时,应尽可能使用弹性比较大的聚合物,而且注入速度须高于临界粘弹流速,这样才能充分利用其粘弹性提高采收率。

The dynamic viscoelasticity and normal theological behavior of hydrophobic association polymer solution（HAPS） as well as the theological behavior of HAPS in porous media were measured. The experimental results of dynamic viscoelasticity of HAPS indicate that the loss modulus （G＂） and elastic modulus （G′） of association polymer solution are higher when the concentration of association polymer（AP） is higher than the critical association concentration. The G＂ is larger than the G′ when concentration of AP is lower than the critical association concentration.and the G＂ is smaller than the G′ when the concentration of AP is higher than the critical association concentration. The G＂ and G′ are free from shear stress in the different concentration of HAPS. Under the experimental shear rate, the macroscopical rheological behaviors of HAPS show shear thinning and shear thickening. In porous media, the rheological behavior of HAPS shows the properties of Newton fluid under the low-speed shear. The shear thinning and shear thickening behaviors could be observed when increasing shear rate. The polymer with a bigger elasticity should be used,and its injecting rate should be higher than the critical viscoelastic flow rate when using hydrophobic association polymer in polymer flooding. In this way, the viscoelasticity of hydrophobic association polymer can he fully utilized to enhance oil recovery.