Viscoelastic fluids formed by an ultralong-chain trimeric surfactant and its application in fracturing fluids

Abstract

In this work, we investigated the structural transitions of aggregates of a trimeric cationic surfactant 3C22quinQ solutions with or without KCl using rheological measurements and molecular dynamic (MD) simulation. Steady and dynamic rheological measurements were used to investigate the rheological properties of 3C22quinQ and 3C22quinQ/KCl systems. The results show that 3C22quinQ can form wormlike micelles at 1 mM without any additives, demonstrating remarkable self-assembly and thickening ability. The addition of KCl further optimizes the molecular configuration and promotes the rapid growth of wormlike micelles. A 11.07 mM 3C22quinQ solution exhibits a zero-shear viscosity η0 of 5.1 × 105 mPa‧s together with relaxation time τR of 36.27 s at a KCl to 3C22quinQ molar ratio of 1. In addition, molecular dynamic (MD) properties such as the radial distribution function (RDF), the radius of gyration (Rg), and mean square displacement (MSD) show that KCl has a considerable influence on the structure and aggregation properties of 3C22quinQ micelles, in good agreement with rheological experimental results. More importantly, the VES fracturing fluid formed by 3C22quinQ and KCl was not only resistant to high temperature and cyclic shear, but it also exhibited excellent proppant-carrying and oil-induced gel-breaking performances. The viscoelastic fluid formed by 3C22quinQ and KCl, has shown promise as an appealing option for hydraulic fracturing procedures in unconventional oil and gas reserviors.