Effect of spacer hydroxyl number on the performance of Gemini cationic viscoelastic surfactant for fracturing fluids

The performance of Gemini cationic viscoelastic surfactant (VES) is affected by the spacer group, which is also the focus for developing the molecular structure design of high-performance clean fracturing fluid. In this study, we synthesized Gemini cationic VESs (VES-O, VES-DO, VES-TO) by introducing different number of hydroxyl groups in the spacer. The effect of the number of hydroxyl groups in the spacer on the performance of Gemini cationic VES was investigated using surface tension measurement, apparent viscosity and viscoelasticity tests in the presence of KCl. Further, the performance of clean fracturing fluids containing VES-O, VES-DO, and VES-TO were evaluated. We discovered that increasing numbers of hydroxyl groups in the spacer improves surfactant performance in fracturing fluid and high-elasticity fracturing fluids with low viscosity. This gives us ideas for future designs of high-performance clean fracturing fluids. (c) 2021 Published by Elsevier B.V.