Faced with the increasing energy demand, enhanced oil recovery plays a progressively more important role in oil production and becomes more and more competitive. Alkali flooding, a chemical EOR method, can be a solution to increment oil recovery especially when it is combined with other techniques. In this study, alkali phase behaviour was studied; two of the most commonly used substances in alkaline flooding applications (sodium hydroxide and sodium carbonate) were compared to discover the most promising chemical formulation for Alkali-Polymer flood. To do so, the evolution of oil, emulsion and aqueous phase was studied over time. Synthetic water and back produced water were evaluated to screen the best water quality to be used. Moreover, to mimic reservoir conditions more realistically, experiments were performed with dead oil as well as viscosity matched oil. Furthermore, the rheology of the generated micro-emulsion was also a core interest for this thesis due to its effect on the efficiency of the flow dynamics, for instance, the high viscous emulsion can result in serious problems in the reservoir like pore blockage, and high polymer slugs are required. Thus, viscosity measurements for WOR 5:5 were conducted for the different alkali-oil prepared samples. The effect of adding co-solvent at different concentration ranges was analyzed. It was found out that the use of co-solvents improves the performance of Alkali-Polymer floods by achieving more stable, less viscous micro-emulsion.