Effect of asphaltene and resins on the stability of water-in-waxy oil emulsions

Asphaltene, resins and paraffin waxes, their mutual interactions and their influence on the stability of water-in-oil emulsions have been studied. 20 wt % paraffin wax dissolved in decalin was used to model the waxy crude oil . Asphaltene and resins separated from a crude oil were used to stabilize t he water-in-oil emulsions. Synthetic formation water was utilized as the aq ueous phase of the emulsion. The emulsion stability increased with increasi ng the concentration of asphaltene with a subsequent decrease in the averag e particle size distribution of the emulsion. Resins alone are not capable of stabilizing the emulsion, however, in the presence of asphaltene they fo rm very stable emulsions. Dynamic viscosity and pour point measurements pro vided evidence for resins-paraffin waxes interactions. Asphaltene in the fo rm of solid aggregates form suitable nuclei for the wax crystallites to bui ld over with a mechanism similar to that of paraffin wax crystal-modifiers. As asphaltene are polar in nature they are derived at the oil/water interf ace which was proved by the ability of asphaltene to reduce oil/water inter facial tension. Consequently, nucleation of the wax crystallites by asphalt ene and resins at the interface will add to the thickness of the oil-water interfacial film and hence increase the stability of the emulsion.