Non-Ionic Surfactants as Boosters for FR Hydration in Brines

A theoretical model of polyacrylamide polymers (PAM and PHPA) hydration dynamics is explored, with emphasis on the effect pf salinity on the hydration dynamics of traditional PAM and PHPA polymers. By understanding the interactions at a molecular level between the polymer and the solvent system it is expected that the polymer’s usability as a viscosifying agent can be extended into brackish and possibly produced water. In this study, viscosity vs. time plots are used to find the hydration rates for PAM and PHPA emulsions in fresh water and various brines. Special brines were designed, including one with Fe(III) among components. The study is done by using common, commercial viscometers, utilizing an R1 B1 bob configuration with heated cup. The overall mixing shear generated is low and kept constant throughout the runs. The temperature and length of runs are also kept constant. This allows the determination of the rate limiting hydration step, maximum viscosity and the hydration rates of a wide variety of nonionic surfactants to be explored. By comparing the PAM and PHPA hydration rates for the neat brine, tap water and brine with non-ionic surfactant it is shown that by choosing the correct nonionic surfactant the hydration rates can be increased by over 3500% from the brine solution and more than 10-50% from tap water. It is also shown that the maximum viscosity can be increased by over 700% from the brine solution and 27% from tap water. This trend was also shown to be true using Nano pure water. The results support the theoretical hydration dynamics we propose, showing the effect the nonionic surfactants have on the rate limiting hydration step and transitions between different hydration steps. The data is strong proof that by understanding the processes of polymer hydration, brackish and possibly produced water in a wide range of TDS can be used to successfully hydrate the polymer. The novelty of this testing is that it provides further examples of how non-ionic surfactants can be used successfully to allow PAM and PHPA polymers to be hydrated in brine waters of various compositions with no damage to performance. Care was taken to utilize very common instrumentation and to develop simple and clear procedures for testing, to make the method easy and reliable to use by field labs that may not necessarily have state-of-the-art equipment available.