Portable rheometer to overcome the challenge of measuring low viscosity solution of acrylamide-based polymers at high temperature with an affordable cost for O&G applications

Abstract

Performances of rotational shear rheometers are sometimes limited to measuring low viscosity at high temperatures of water-based polymer solutions. These limitations are typically due to the instrument resolution, sample inertia, and volumetric effects. Moreover, such measurements are not possible for temperatures exceeding 80 °C because of evaporation phenomena leading to a distortion of the value. The working principle of rheometers suitable for measuring viscosity above the boiling temperature reduces their sensitivity and limits their use to high-viscosity fluids. Acrylamide-based polymers are viscoelastic complex fluids exhibiting non-Newtonian behavior. Their viscosifying properties are strongly related to their charge density, molar mass, temperature, and salinity. The prediction of their rheological properties at high temperatures is challenging and is often extrapolated with an empiric law, such as Arrhenius equation. To the best of our knowledge, no commercially available rheometers are capable of measuring low viscosity of water-soluble complex fluids at high temperatures. In this work, we investigate a home-made fully automated capillary rheometer that has been developed to give an accurate measurement of viscosity and intrinsic viscosity of polymer solutions. This device is an affordable cost portable apparatus compared with a commercialized rheometer specifically designed for a wide range of viscosities and temperatures for various applications. The intrinsic viscosity has been measured on two acrylamide-based polymers of different chemical compositions using the capillary rheometer at high temperatures. This device has also been explored for measurement of a water-soluble polymer solution viscosity commonly used in enhanced oil recovery applications to limit chemical degradation.