Effect of drag reducing polymers on surfactant-stabilized water–oil emulsions flow

Abstract

In this paper, the effect of drag reducing polymers (DRP) on the flow characteristics of surfactant stabilized water–oil emulsions was investigated. Oil soluble polymers as well as water soluble polymers were tested as drag reducing agents for stable and unstable water-in-oil and oil-in-water emulsions. Pressure drop measurements were conducted in 2.54-cm and 1.27-cm horizontal pipes. The influence of DRP type, concentration and molecular weights on emulsion stability, viscosity and pressure drop were reported.The results showed a significant increase in the emulsion stability with adding the proper DRP and this effect was enhanced as DRP molecular weight increased at ambient temperature. In addition, emulsion stability as well as DRP effect on emulsion stability was reduced as temperature increased. Injecting the right DRP (which is soluble in emulsion external phase) resulted in a pressure drop reduction for all tested stable emulsion types (concentrated water-in-oil (W/O), oil-in-water (O/W) and W/O) and this effect increased as DRP concentration increased. However, injecting DRP which is soluble in the internal (dispersed) phase showed a drag reduction effect for unstable emulsion but with less extent. Moreover, injecting all types of DRP for emulsion flow with the same turbulence intensity (same Re) showed almost no dependency on the pipe diameter.