Shear behavior at high pressures and viscoelastic properties in water and in brine solutions with high salinities for a tetra-polymer containing poly(ethylene oxide) side chains

Abstract

A novel tetra-polymer (PASV) was synthesized using acrylamide(AM), vinyl biphenyl (VP), sodium 2-acrylamido-2-methylpropane sulphonate (NaAMPS), and a novel salt-tolerant macromonomer, allyl-capped octylphenoxy poly(ethylene oxide) with the polymerization degree of 4 (AE). Consecutive shear behaviors of PASV were investigated at high pressures of 5–20 MPa as well as atmospheric pressure to reveal rheological performance of oil-flooding polymers in oil reservoirs. PASV displays an excellent thickening effect induced by salt as well as good associated behavior in aqueous solutions. Its critical association concentrations are merely 0.7 g L⁻¹ and 0.6 g L⁻¹ in aqueous solution and in 70 g L⁻¹ NaCl, respectively. PASV in 70 g L⁻¹ NaCl exhibits not only obvious shear thickening behavior but also unreported pressure-thickening behavior in an investigated pressure range of atmospheric pressure to 20 MPa at 65 °C. PASV also displays predominantly unexpected elastic behavior both in water and in brine solutions with high NaCl concentrations.