联结基团对甜菜碱型双子表面活性剂清洁压裂液性能的影响

Effect of spacer on the performance of Gemini betaine surfactant in clean fracturing fluid

甜菜碱型双子表面活性剂因具有低污染、低伤害优势,可作为清洁压裂液应用于油田开采。以芥酸、N,N-二甲基-1,3丙二胺、3-氯-2-羟基丙磺酸钠为原料,分别以六亚甲基二异氰酸酯(简称HDI)、甲苯二异氰酸酯(简称TDI)、异佛尔酮二异氰酸酯(简称IPDI)为联结基团,合成了不同联结基的甜菜碱型双子表面活性剂GAS-22-n(n=IPDI,HDI,TDI),研究了联结基团对其性能的影响。实验结果表明:GAS-22-HDI结构中的柔性基团长碳链易于弯曲,分子间作用力强,受外力影响较小,更易形成胶团,使其具有良好的抗盐性、较低的表面张力和cmc值。而GAS-22-TDI结构中的刚性基团苯环体积较大,胶束聚集形成较粗的蠕虫状聚集体,进一步构成致密的三维网络结构,赋予其良好的耐温耐剪切性、悬砂性和黏性。

Gemini betaine surfactants have the advantages of low pollution and low damage,which can be used in clean fracturing fluids for oilfield development.In this work,three Gemini betaine surfactants GAS-22-n(n=IPDI,HDI and TDI)with different spacers were synthesized by using erucic acid,N,N-dimethyl-1,3-propanediamine and sodium 3-chloro-2-hydroxypropanesulfonate as raw materials,and hexamethylene diisocyanate,toluene diisocyanate and isophorone diisocyanate as spacers.The effects of spacers on the properties were studied.The experimental results showed that,the long carbon chain of the spacer in GAS-22-HDI structure was flexible and easy to bend,exhibiting strong intermolecular interactions and being less influenced by external forces,which made it easier to form micelles and have good salt resistance,low surface tension and low cmc.The rigid benzene ring in GAS-22-TDI structure had a larger volume,and the micelles fused to form wormlike aggregates,further forming a dense three-dimensional network structure,endowing it with good temperature resistance,shear resistance,sand suspension,and viscosity.