ABSTRACT To obtain a new fracturing fluid viscosifier, hexadecyl dimethyl amine was used to modify carboxymethyl hydroxyethyl cellulose (CMHEC) to obtain a product called HD-CMHEC with high viscosity. The rheological properties of HD-CMHEC solutions and CMHEC solutions were studied. For the concentration of 0.3%, the viscosity of CMHEC and HD-CMHEC solutions is, respectively, 19.0 mPa · s and 73.6 mPa · s, respectively. The viscosity of HD-CMHEC solution increases 2.8 times than before. The thixotropy and viscoelasticity of HD-CMHEC solutions become stronger. As a typical viscoelastic fluid, HD-CMHEC solutions show better rheological performance than that of CMHEC solutions. The gelling process of HD-CMHEC solutions under steady shear was studied in detail. The concentrations of HD-CMHEC solutions, shear rates, and crosslinking agent were investigated. Viscosity versus time curves during the crosslinking process were obtained. The four-parameter crosslinking rheokinetics equation can describe the gelling process of HD-CMHEC solutions under different conditions well. Study on the gelling process of HD-CMHEC solutions under steady shear contributes to the understanding of gel formation, and provides theoretical guidance for exploration and exploitation of the system. GRAPHICAL ABSTRACT

中文翻译：

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十六烷基二甲胺改性羧甲基羟乙基纤维素溶液的流变特性及其胶凝过程

摘要 为获得新型压裂液增稠剂，采用十六烷基二甲胺对羧甲基羟乙基纤维素（CMHEC）进行改性，得到高粘度产品HD-CMHEC。研究了HD-CMHEC溶液和CMHEC溶液的流变特性。当浓度为0.3%时，CMHEC和HD-CMHEC溶液的粘度分别为19.0 mPa·s和73.6 mPa·s。HD-CMHEC 溶液的粘度比以前增加了 2.8 倍。HD-CMHEC 溶液的触变性和粘弹性变强。作为一种典型的粘弹性流体，HD-CMHEC 溶液表现出比 CMHEC 溶液更好的流变性能。详细研究了HD-CMHEC溶液在稳定剪切下的胶凝过程。HD-CMHEC 溶液的浓度、剪切速率、和交联剂进行了研究。获得了交联过程中的粘度与时间曲线。四参数交联流变动力学方程可以很好地描述HD-CMHEC溶液在不同条件下的胶凝过程。研究HD-CMHEC溶液在稳态剪切下的胶凝过程有助于理解凝胶的形成，并为该体系的探索和开发提供理论指导。图形概要 并为系统的探索和开发提供理论指导。图形概要 并为系统的探索和开发提供理论指导。图形概要