一种疏水缔合聚合物水溶液的黏弹性与减阻特性研究

Performance Study on Viscoelastic and Drag Reduction of a Hydrophobically Associating Polymer

本文考察了一种疏水缔合聚合物BCG-1溶液的黏弹性,使用自制的流动回路摩阻测试系统测定了不同浓度下疏水缔合聚合物水溶液的摩阻性并进行了现场试验。实验结果表明:不同浓度的BCG-1水溶液的第一法向应力差N1均随剪切应力的增大而增加,高剪切应力条件下,表现出更强的弹性效应,且浓度越大,相同剪切应力条件下第一法向应力差N1的值越大;浓度小于临界缔合浓度时,G'小于G'',分子链之间的缔合作用较弱,溶液中没有形成有效的空间结构,随着BCG-1浓度高于临界缔合浓度后,G'大于G'',分子链之间的缔合作用增强;随着浓度的增加,疏水缔合聚合物溶液的G'和G''逐渐接近平行,疏水缔合作用对黏弹性的贡献所占比例逐渐减小,分子主链之间的相互缠结作用对黏弹性的贡献所占比例逐渐增大。降阻率随浓度的增加先上升后降低,在强剪切作用下,分子主链之间解缠结作用所需时间更长,水溶液的流动性减弱,降阻能力反而下降。增加相对分子质量并不是提高聚合物降阻能力的唯一方法,疏水缔合聚合物浓稠水溶液体系同样具有良好的降阻能力,现场施工表明,最高降阻率超过70%。

In the paper,the viscoelasticity of hydrophobic associating polymer BCG-1 solution was investigated,the frictional resistance of the BCG-1 solutions with different concentration was examined using homemade flow loop testing system and the filed test was conducted. Experimental results showed that the first normal stress difference N1 of the BCG-1 aqueous solutions with different concentrations increased with shear stress increasing,moreover,Under high shear stress,a more elastic effects was shown,the higher concentration,the greater the values of the first normal stress difference N1 at the same shear stress. When the concentration of the BCG-1 aqueous solutions was less than the critical associating concentrations,G' was less than G'',the association was weaker between the molecular chains,and an effective spatial structure did not form,after the concentration of BCG-1 was above of critical associating concentrations,G' was greater than G'',the association between molecular chains increased. As the concentration increased,the curve of G' and G'' of BCG-1 solution was gradually closer to parallel,the viscoelastic contribution percentage of the hydrophobic association decreased,while the viscoelastic contribution percentage of molecular interaction between main chain entanglements increased. The drag reduction rate first increased and then decreased as the concentration increased,under strong shear force,the disentanglement between the hydrophobic associating polymer main chain required longer time,and the aqueous liquidity weakened,resistance-reducing capacity reduced. It is not the only way to increase the relative molecular weight to improve resistance-reducing capability of polymer. Hydrophobic associating polymer thick water solution system also had good resistance reduction capability. The field construction showed that the maximum Drag reduction rate was of over 70%.