Organic Acid-Enhanced Viscoelastic Surfactant and Its Application in Fracturing Fluids

Viscoelastic surfactant (VES) fracturing fluids, with the advantages of low residues, complete gel breaking, and low formation damage, have received considerable attention in hydraulic fracturing techniques. However, the complicated synthesis process and high costs limit the widespread application of VESs. Herein, a VES fracturing fluid composed of wormlike micelles was developed by coupling an ultralong hydrophobic chain surfactant N-erucamidopropyl-N,N-dimethylamine (EA), with p-phthalic acid (p-PA), which behaved as a Gemini-like surfactant via noncovalent interactions. The macroscopic appearance and viscosity of this fluid were responsive to the regulation of pH values. Then, the related fracturing performance of this fluid was systematically investigated, from which it could be concluded that the VES fluid exhibited good temperature and shear resistance, excellent proppant-carrying and gel-breaking abilities and also caused less damage to core permeability and low corrosion of steel under acidic conditions. Finally, the rheological properties of the VES fluid could be switched multiple times without any decay by changing the pH values, indicating its excellent reusability for fracturing procedures. Consequently, this study demonstrates potential applications of reusable VES fracturing fluids based on supramolecular pH-responsive surfactants.

Automated summary

The VES fracturing fluid developed in this study exhibited good temperature and shear resistance, excellent proppant-carrying and gel-breaking abilities, and caused less damage to core permeability and low corrosion of steel under acidic conditions. The rheological properties of the VES fluid could be switched multiple times without any decay by changing the pH values, indicating its excellent reusability for fracturing procedures. This study demonstrates the potential applications of reusable VES fracturing fluids based on supramolecular pH-responsive surfactants.