This thesis presents the results of a series of experiments conducted on a seven-stage Electrical Submersible Pump (ESP) operating at constant rotating speed with two different mineral oils with viscosities of 10 cP and 125 cP (at 80 °F) respectively. The objective was to study the effect of the water fraction change on the performance of the pump. The operating curves for the third stage were registered for each oil while changing the water fraction. The effective viscosity of the emulsions, were measured using a pipe viscometer set after the pump. Along with the experimental results, CFD simulations using ANSYS CFX 14.0 were carried out to understand the behavior of the phases as they circulated through the third stage.

For both oils, the results showed a decrement in the head and flow rate capacity in the stage and a dramatic increment in the effective viscosity of the W/O emulsion as the water fraction increased before the inversion point. The opposite happened as the water fraction increased after the inversion point for the O/W emulsion.

Using the experimental data of the effective viscosity of the emulsion in a mechanistic model, to calculate the dispersed droplet diameter, the CFD simulations replicated closely the ESP performance for fractions of the dispersed phase up to 20% for a constant specific speed.

An empirical model for the pump performance prediction is suggested based on existing models for effective viscosity of oil and water emulsions.