The relative influence of oil type and temperature on the characteristics of oil droplets stabilized by mineral particles (oil-mineral aggregates-OMA) was studied in the laboratory. OMA were generated by shaking eight different oils under two temperatures with natural mineral fines in seawater at a pre-defined energy level. Shape, mean and maximum sizes, size distribution and concentration of oil droplets forming negatively buoyant OMA were measured by image analysis using epi-fluorescence microscopy. Results showed that oil droplets are, on average, spherical regardless of oil composition and temperature. Non-spherical "elongated" oil droplets form more at 20 degreesC than at 0 degreesC. Droplet shape and size were not correlated to oil viscosity. The concentration of oil droplets decreased rapidly with oil viscosity, temperature and asphaltenes-resins content (ARC). When normalized with ARC, mass concentration of oil droplets correlates well with oil viscosity, regardless of experimental temperature. A model was proposed to calculate mass of oil dispersed by OMA as a function of oil viscosity and ARC. Size distributions of oil droplets follow similar trends, but their magnitudes depend on oil type and temperature. A function was derived that describes all the data when size distributions were presented in a normalized form N/N-t = f (D/D-50), where N is number of droplets of diameter D, N-t is the total number of droplets and D-50 the mean size of the droplets. (C) 2003 Elsevier Science Ltd. All rights reserved.