Impact of the Temperature, Homogenization Condition, and Oil Property on the Formation and Stability of Crude Oil Emulsion

Water-in-oil (W/O) emulsions have garnered significant attention in the petroleum industry as a result of their adverse effects, such as reduced oil recovery, increased pressure drop, and equipment corrosion. This study investigated the influences of the temperature, homogenization conditions, and crude oil properties on emulsion formation and stability. We focused on nine crude oils with varying viscosities, observing the emulsion formation process and analyzing functional groups, percentage of resolved water, and emulsion particle sizes. Under all conditions, W/O emulsions for most oils underwent a transformation from multiple emulsions, including water-in-oil-in-water (W/O/W) and water-in-oil-in-water-in-oil-in-water (W/O/W/O/W) emulsions. As the temperature increased, the variation in the W/O emulsion amount at the end of the transformation differed on the basis of oil viscosity, while emulsion stability showed no significant differences. However, W/O emulsion stability increased after 24 h of aging at high temperatures. Additionally, four hypotheses regarding the final changes in the W/O emulsion amount with the temperature were consistent with the emulsion formation process. With regard to the effect of homogenization conditions, increasing shear intensity resulted in a larger amount of W/O emulsion with high stability. This was attributed to changes in the activity of different natural surfactants with increasing shear intensity. Furthermore, the final amount of W/O emulsion was primarily influenced by hydrogen-bonded O–H, followed by hydrogen-bonded N–H. The mechanisms underlying the influence of different factors on emulsion formation and stability are described.