Systematic Study of Heavy Oil Emulsion Properties Optimized with a New Chemical Formulation Approach: Particle Size Distribution

The purpose of this research was to create very polydisperse concentrated heavy oil-in-water emulsions by optimizing the co-solvents, surfactants, alkali, and electrolytes in the chemical formulation, with respect to the droplet size distribution. Novel co-solvents that have shown superior performance in chemical formulations used for enhanced oil recovery have been tested. Droplet size distributions that resulted in a lower emulsion viscosity were determined to have a higher mean droplet diameter (d 32) and a bimodal droplet size distribution with a diameter ratio (d 32,L/d 32,S) of > 6 and a volume fraction (φS/(φL + φS)) of 0.2–0.3, where φ is the volume fraction of the dispersed phase and the subscripts L and S correspond to the larger and smaller peaks in the bimodal distribution. We report the effects of various chemical formulations on the droplet size distribution of heavy oil-in-water emulsions with a particular emphasis on d 32 and, for the first time, the maximum packing fraction (φm) of oil droplets. A novel one-step preparation procedure is proposed to prepare concentrated multimodal oil-in-water emulsions with a new chemical formulation approach. We were able to formulate stable oil-in-water emulsions with φm values as high as 0.95, which is ∼0.30 higher than the theoretical φm value for random close packed monodisperse spheres (0.64). We observed the optimal particle size distribution of concentrated heavy oil-in-water emulsions prepared with co-solvents for maximum packing at ∼75% of the Na+ concentration necessary to reach the oil-in-water to water-in-oil inversion point for anionic surfactants. An important application of this study is the transport of heavy oils in pipelines.