Water-in-crude oil emulsion stability investigation

The water-in-crude oil emulsion has great importance in the oil industry. The stability of water-in-crude oil emulsion is investigated over a wide range of parameters. These parameters arc water concentration (10-50%), surfactant concentration (0.1-1%), mixing speed (500-2,0001 rpm), salt concentration (0-5%), polymer concentration (0-1,000 ppm), and temperature (13-40 degrees C). The physical properties of water-in-crude oil emulsion in terms of density, viscosity, and interfacial tension are measured by Pycnometer, Ostwald viscometer, and spinning drop tensiometer, respectively. The stability of water-in-crude oil emulsion is studied for each case in details. This investigation shows that the presence of the emulsifying agent is necessary for stable emulsion, and stability gradually decreases with water concentration. The presence of 5% NaCl or 1,000 ppm of Alcoflood polymer provides 100% stable emulsion. Emulsion stability reduces with temperature. Impeller type has a strong effect on the emulsion stability. S-curved blade impeller provides 100% stable emulsion for more than 2 days.