The efficiency of migration and profile control with emulsion systems in class III reservoirs.

In order to reveal the migration law and profile control efficiency of the emulsion system in the core of class III reservoir (the permeability less than 100 mD), the influence of the size and distribution of the droplets, the effect of the migration law and the adjustment of the interlayer contradiction to class III reservoir are studied in this paper. By measuring the droplet distribution in the emulsion system, we found that the average droplet diameter decreases with the increase in water cut. But, the droplet distribution is the most uniform when the water cut is 50%, which is the transition point of the emulsion. Through the core seepage test, the pressure is measured when the emulsion system is flowing through the core. It can be seen that the emulsion flowing is related to the resistance coefficient, the viscosity of the chemical agent and the core permeability; that is, the greater the resistance coefficient, the greater the viscosity of the chemical agent, the smaller the core permeability is and the higher the level of the emulsion is. The matching chart between different emulsion systems and layers with different permeability of class III reservoir was established. The effect of profile control with different permeability contrasts was predicted according to the matching chart. The emulsification has a positive effect on the enhancement of recovery when the permeability contrast is small, but a negative effect when the permeability contrast is larger. The study of the emulsion migration and profile control efficiency in class III reservoir are of great significance for understanding the emulsification in class III reservoirs.