Figure 3—Transitions of the viscous finger and droplet formation (a): steam injection into heavy oil at 200°C (b): steam injection with Tween 80 (polysorbate 80) into heavy oil 200°C, (c): CTAB (cationic surfactant) injection at 25°C.
To investigate further on the droplet development behavior, in this paper, we attempted to account for the observed experimental data with a specified focus on the droplet generation stage of the emulsion flow by comparing the self-similarity behavior of fingers before and after the finger stability loss. To achieve this, we first employed a fractal analysis approach. We have specifically selected the solution samples that have resulted in droplet generation at a certain stage of the experiments and the solutions range widely in IFT (0.02 to 17 mN/m) and viscosity ratio (7.22×10-5~5.71×10-2) which makes it appropriate to explore the universal fractal characteristics of in-situ emulsion development in a Hele-Shaw model. Then we investigated the functional relationship between the selected parameters and various dimensionless scaling groups to enhance our understanding of the influence that each parameter has on droplet formation in emulsion flow and explore the relevant mechanisms.