基于UCST的低浓热增粘聚合物制备及构效关系与热增粘机制研究

聚合物水溶液粘度一般会随温度升高而减小，在高温油藏的应用受到了限制，热增粘可根本上解决这一问题。引入LCST结构，温度升高溶解性下降，发生分子间缔合可实现热增粘，但需较高浓度，限制了其应用。若UCST聚合物的温敏性主要来自于焓变驱动，适度降低UCST单元含量制备高分子量聚合物，在室温可溶的同时，相互作用及水力学尺寸随温度升高而有较大幅度增加，则可实现基于大分子构象改变的低浓度热增粘。选取不同类型UCST共聚体系，合成不同组成分子量较高的聚合物，考查水溶性、低浓溶液粘-温关系，得到可低浓热增粘的聚合物和共聚体系。考查UCST单元性质、含量、分子量，浓度等因素的影响，得到构效关系。采用光散射，DSC、FDSC差谱及FTIR二维相关分析考察分子间作用、水力学尺寸随温度的变化，结合构效关系及粘流表观活化能综合分析，揭示热增粘机制，可为制备低浓热增粘聚合物驱油剂打下基础，促进高温油藏聚合物驱的应用。

The viscosity of polymer aqueous solution usually decreases with the increase of temperature, which limits the application of polymer flooding in high-temperature reservoirs. The thermoviscosifying technology can fundamentally solve the problem of viscosity decrease with temperature rising. When lateral chains with low critical solubility temperature (LCST) are introduced into water soluble polymer, the solubility of copolymer would decrease with temperature rising and intermolecular association occur. As a result, the viscosity of polymer aqueous solution increases, namely thermoviscosifying. However, intermolecular association requires a higher copolymer concentration, which limits its application. .If the thermo-sensitivity of UCST polymer is mainly driven by enthalpy change, polymer with higher molecular weight can be prepared by moderately reducing the content of UCST unit, which can be soluble at room temperature and the interaction in solution and hydraulics size of polymer increases greatly with the increase of temperature, and then, the low-concentration thermoviscosifying can be realized based on the conformation change of macromolecules..Polymers with higher molecular weight and different components are synthesized from different UCST copolymerization systems. The low concentration thermoviscosifying polymers and copolymerization systems can be obtained through investigating the water-solubility and viscosity-temperature relations at low concentration. The structure-function relationship can be obtained via exploring the effects of contents of UCST units, molecular weight of copolymer and polymer concentration on properties. Light scattering, FDSC difference spectrum, FTIR two-dimensional correlation analysis will be adopted to explore the variations of intermolecular interaction, hydrodynamic size and viscosity with temperature. Analyze the relationship between them and thermoviscosifying behavior systematically, combined with structure-function relationship and apparent activation energy of viscous flow, the mechanism of thermoviscosifying would be revealed. It can not only lay a foundation for preparing thermoviscosifying polymer flooding agent which can thicken with temperature rising at low polymer concentration, but also promote its application in high-temperature reservoir.