Methods for producing seawater based, high temperature viscoelastic surfactant fluids with low scaling tendency

A viscoelastic surfactant fluid comprising:

• a viscoelastic surfactant comprising the general formula:
• where R1 is a saturated or unsaturated hydrocarbon group of from 17 to 29 carbon atoms, R2 and R3, are each independently selected from a straight chain or branched alkyl or hydroxyalkyl group of from 1 to 6 carbon atoms, R4 is selected from H, hydroxyl, alkyl or hydroxyalkyl groups of from 1 to 4 carbon atoms;
• k is an integer of from 2-20;
• m is an integer of from 1-20;
• and n is an integer of from 0-20;
• at least one nanoparticle viscosity modifier having a particle size of 0.1 to 500 nanometers and comprising one or more of carbon nanotubes, Zr compounds, Ce compounds, Al compounds, B compounds, Sn compounds, Cr compounds, or Si compounds;
• desulfated seawater, where the desulfated water is free of CaSO4 precipitate;
• and
• at least one stabilizing calcium salt.