Abstract: A viscoelastic surfactant (VES) for a self-diverting acid under high temperature has a structural formula shown as formula (I), wherein, n is saturated hydrocarbon with 2 to 8 carbon atoms; R1 is saturated or unsaturated hydrocarbon with 18 to 28 carbon atoms; R2 and R3 are independently methyl, ethyl or hydrogen, and R2 and R3 can be the same or different; and X? is any one of Cl?, Br?, CO32?, SO42?, HCOO? and CH3COO?. The method for preparing the surfactant includes subjecting a fatty acid and an organic amine to acid-amine condensation to obtain an intermediate. The intermediate reacts with a metal hydride to obtain a fatty amine. Then, an acid solution is used to protonate the fatty amine to obtain an ultra-long-chain viscoelastic cationic surfactant. The present invention also provides use of the surfactant as a thickener for a self-diverting acid.

Abstract: A viscoelastic surfactant (VES) for a self-diverting acid under high temperature has a structural formula shown as formula (I), wherein, n is saturated hydrocarbon with 2 to 8 carbon atoms; R1 is saturated or unsaturated hydrocarbon with 18 to 28 carbon atoms; R2 and R3 are independently methyl, ethyl or hydrogen, and R2 and R3 can be the same or different; and X? is any one of Cl?, Br?, CO32?, SO42?, HCOO? and CH3COO?. The method for preparing the surfactant includes subjecting a fatty acid and an organic amine to acid-amine condensation to obtain an intermediate. The intermediate reacts with a metal hydride to obtain a fatty amine. Then, an acid solution is used to protonate the fatty amine to obtain an ultra-long-chain viscoelastic cationic surfactant. The present invention also provides use of the surfactant as a thickener for a self-diverting acid.

Abstract: A method for preparing an anionic thermoviscosifying water-soluble polymer includes the following steps: performing an inverse emulsion polymerization by using acrylamide, acrylic acid and Pluronic triblock polymer. The high reactivity of acrylamide and the inverse emulsion polymerization can increase the molecular weight of the thermoviscosifying polymer, and exhibit an obvious thermoviscosifying effect even at a low polymer concentration, which can reduce the application cost. The dissolution rate of the obtained polymer emulsion is significantly higher than the dissolution rate of the dry powder of the polymer. The obtained emulsion-diluted solution has a relatively strong thermoviscosifying behavior after further adding a small amount of reverse demulsifier, and the emulsion-diluted solution exhibits different thermoviscosifying behaviors as the amount of the reverse demulsifier is increased.

Abstract: A method for preparing an anionic thermoviscosifying water-soluble polymer includes the following steps: performing an inverse emulsion polymerization by using acrylamide, acrylic acid and Pluronic triblock polymer. The high reactivity of acrylamide and the inverse emulsion polymerization can increase the molecular weight of the thermoviscosifying polymer, and exhibit an obvious thermoviscosifying effect even at a low polymer concentration, which can reduce the application cost. The dissolution rate of the obtained polymer emulsion is significantly higher than the dissolution rate of the dry powder of the polymer. The obtained emulsion-diluted solution has a relatively strong thermoviscosifying behavior after further adding a small amount of reverse demulsifier, and the emulsion-diluted solution exhibits different thermoviscosifying behaviors as the amount of the reverse demulsifier is increased.