Abstract
In this study, the influence of organoclays (OC) on the pressure drop of surfactant-stabilized water-in-oil (W/O) emulsions was studied. OC were tested as pressure loss reducing agents for stable W/O emulsions with 0.7 (concentrated) and 0.3 (diluted) water volume fractions. Pressure drop measurements were conducted in horizontal pipes with inside diameters (ID) of 0.0254-m and 0.0127-m. The results showed a significant reduction in the emulsion viscosity with the addition of OC and this effect was enhanced as the concentration increased. In addition, for the case of concentrated W/O emulsions, the addition of OC resulted in 25% reduction in the emulsion pressure drop in both test sections. For diluted W/O emulsion with only 03 water fraction, while no pressure drop reduction was observed in the laminar region, it was detected in the turbulent region and such effect was pronounced at high Reynolds numbers and high OC concentration. The observed results were explained in terms of emulsion dispersed phase droplet size. In the laminar regime, the friction factor for stable W/O emulsions was in a good agreement with single phase predictions. However, in the turbulent regime the friction factor for the multiphase system was below the predictions of single phase flow. OC proved to have a good potential as drag reducing agents by producing smaller and stable emulsion droplets hence suppressing the Reynolds' stresses. (C) 2014 Elsevier B.V. All rights reserved.