The co-production of crude-oil and water results in water-in-oil emulsion system. The emulsion formed may cause problems in the reservoir, subsea and surface equipment, thus hindering separation and production. It is thus, imperative to enhance an understanding in emulsion characteristics of different crude-oil. This work presents the study of the water-in-crude-oil emulsion in which, the gravity settling, the critical-electric-field (CEF) and the centrifuge methods were used to evaluate the stability of the emulsions. The gravity test method was evaluated at a constant temperature of 60°C. Fractional factorial design was used to estimate the stability of the emulsion formed; water cut (volume fraction of the water), brine pH, stirring speed and stirring time were chosen as the main factors for the experiment. From the experiments performed on Hebe-1 crude-oil it was found that for the gravity test method all the variables had a significant effect, although the stirring speed was the most significant effect followed by the stirring time, pH and water cut respectively. Results from the centrifuge test method showed that the most important variable was the stirring speed followed by water cut and brine pH consecutively. For the CEF test method all the factors and their interactions had a significant effect on the critical voltage measured, however the stirring speed was the most important variable followed by the water cut.