Optimization of Heat and Chemical Applications toward Effective Emulsion Resolution

Water-in-oil emulsions are unstable colloidal dispersions with water as the dispersed phase and oil as the continuous phase. Water-in-oil emulsions are the most common emulsions found in the oil field. It occurs in almost every phase of the oilfield from the sand face to the surface. Emulsion constitutes numerous problems in the oil and gas industry ranging from flow problems due to high viscosity of emulsions to increase in cost in the use of demulsifiers. In resolving emulsions, heat, chemical or a combination of both methods can be used. Demulsifiers destabilizes the emulsifier film in the emulsion and thus rupture the film to resolve the emulsion. While heat decreases the viscosity of the emulsion by increasing the entropy of the system. The heat excites the enclosed water molecules and thus rupture the film.
Research has shown that the use of chemical and heat to resolve emulsion is effective. In this study, synthetic emulsions in water-oil ratios of 20/80 and 50/50 were formed in the laboratory. Emulsions were separated into 10 ml measuring cylinders, then 0.5 ml of demulsifier was added before exposing it to heat from a domestic microwave oven. Three cases were experimented; the use of microwave heat only, demulsifier only and the use of both demulsifier and microwave heat.
The results obtained showed the effectiveness in the combination of heat and chemical in emulsion resolution. 70% water was recovered for the case of 20/80 water-oil ratio at a microwave exposure of medium low microwave power (336 Watt) for 60 seconds. In the 50/50 water-oil ratio, 100% water was recovered with just demulsifier use.
In resolving tight water-in-oil emulsions, the synergy effect of heat and chemical is required for effectively resolving the emulsions. The findings showed an optimal exposure time to which the emulsion should be heated, after which it is a waste of energy to continue heating. It is recommended that this procedure be repeated for varying amount of demulsifier. Furthermore, various water-oil ratios such as 10/90, 30/70, 40/60 should be experimented using this method to understand and analyse the effect on water-oil ratio in resolving emulsions using a combination of microwave and demulsifier.