In this study, oil production and retention were observed and compared in 72 reservoir simulation cases, after which an economic analysis for various CO₂ and oil prices was performed. Reservoir simulation cases comprise different combinations of water alternating gas (WAG) ratios, permeabilities, and well distances. These models were set at three different depths; thus different pressure and temperature conditions, to see the impact of miscibility on oil production and CO₂ sequestration. Those reservoir conditions affect oil production and CO₂ retention differently. The retention trend dependence on depth was not monotonic—optimal retention relative to the amount of injected CO₂ could be achieved at middle depths and mediocre permeability as well. Results reflecting different reservoir conditions and injection strategies are shown, and analysis including the utilization factor and the net present value was conducted to examine the feasibility of different scenarios. The analysis presented in this paper can serve as a guideline for multiparameter analysis and optimization of CO₂-enhanced oil recovery (EOR) with a WAG injection strategy.