VISCOSITY OF WATER IN OIL EMULSIONS

Abstract

ABSTRACT Increase in water cut in oil fields generally calls for an increase in the capacity of transport pipelines. Proper design and operation of the latter requires good knowledge of the thermophysical properties of flow resistance of crude-oil water mixtures. An experimental program aimed at measurements of oil-water emulsion viscosity for water cuts prior to the inversion point was conducted. The present work reports on measurements of Nimr crude oil-water mixtures viscosity for different water cuts and a typical range of temperatures representative of field conditions (20°-50°C). Three mixing intensities of 106, 5×106 and 15×106 erg/cm-sec generated by a dynamic coalescer and directly relevant to field conditions were used. The results suggest that the inversion point occurs around a value of water cut of 35%. Both Newtonian and non-Newtonian (pseudo-plastic) behaviour were observed, and the ASTM viscosity model is found to be applicable to the emulsions. The effect of the mixing intensity on the resulting emulsion viscosity was found to be important at low temperatures and decreased at high temperatures. The experimental data fitted the available correlations in the literature.