Steady Shear and Dynamic Properties of Drag Reducing Surfactant Solutions

Abstract

The rheological behavior of oilfield surfactants (Aromox® APA-T and APA-TW) at various concentrations was studied using steady shear and dynamic testing. The results showed that the solutions exhibit non-Newtonian behavior at all concentrations, with their rheological character influenced by the temperature and ionic content of the base fluid. Temperature was observed to have a significant effect on viscosity and dynamic data. The apparent viscosity at different temperatures could be reduced to a single master curve using horizontal and vertical shift factors. However, satisfactory scaling could not be attained for the dynamic or viscoelastic data. Molecular scaling using characteristic time for data at different concentrations proved unsuccessful due to the strong non-Newtonian character of surfactant solutions. Scaling relations between rheological parameters and concentration indicated the presence of long micelles in APA-T solutions. APA-TW solutions, on the other hand, contained branched micelles.

Keywords

• surfactants
• non-newtonian behavior
• rheology
• viscoelasticity
• concentration
• temperature