Abstract: New clean fracturing fluid VES⁃YF was prepared by mixing the betain type amphoteric surfactant YF⁃1 and cosurfactant YF⁃2 with KCl. By measuring the influence of different concentration of YF⁃1, YF⁃2 and KCl on the viscosity of fracturing fluid, the optimized formulation was obtained, which is 2.0%YF⁃1+1.0%YF⁃2+2.0%KCl. The research and evaluation of the system's construction mechanism and its applicable performance were conducted. The results show that VES⁃YF clean fracturing fluid has shear thinning property and good viscoelasticity. The rheological measurement shows that the network structure of worm⁃like micelle exists in the system and can be recovered after shear failure. The apparent viscosity of VES⁃YF clean fracturing fluid is still higher than 80 mPa·s after shearing for 2 h at the temperature of 45 ℃ and the shearing rate of 170 s-1. The system has the advantages of strong sand carrying capacity, good gel breaking property and low core damage rate. VES⁃YF clean fracturing fluid has a broad application prospects in the fracturing operation of low permeability reservoir.

Key words: Clean fracturing fluid, Wormlike micelles, Shear thinning property, Viscoelasticity, Performance evaluation

摘要： 采用甜菜碱型两性表面活性剂YF⁃1与助表面活性剂YF⁃2复配，并在KCl作用下得到新型清洁压裂液VES⁃YF，通过测定不同浓度YF⁃1、YF⁃2、KCl对体系黏度的影响，优化出VES⁃YF清洁压裂液最佳配方（质量分数）：2.0%YF⁃1+ 1.0%YF⁃2+2.0%KCl，并对体系的构筑机制和适用性能进行评价。结果表明，VES⁃YF清洁压裂液具有剪切变稀性和良好的黏弹性，流变测量显示体系中存在蠕虫状胶束网络结构，能在剪切破坏后得到恢复。VES⁃YF压裂液在45 ℃、170 s-1条件下剪切2 h后，表观黏度保持在80 mPa·s以上。体系具有携砂能力强、破胶性能良好、岩心伤害率低等优点，在低渗储层压裂改造中具有良好的应用前景。

关键词: 清洁压裂液, 蠕虫状胶束, 剪切变稀性, 黏弹性, 性能评价