Enhanced oil recovery (EOR) processes are used to alter the properties of rock or fluids within an oil reservoir to cause additional crude oil recovery from mature oilfields. In gas injection EOR, gases are injected to improve oil mobility within the reservoir. CO2 is often used as a miscible gas for this technique. Besides being less expensive than other similarly miscible gases, it creates opportunities for Carbon Capture, Utilization, and Storage (CCUS) projects. The Minimum Miscibility Pressure (MMP) is a critical parameter for any miscible gas injection project because it indicates the pressure threshold above which the gas mixing will be uniform and efficient. The slim tube experiment is one of the most commonly used methods of estimating the MMP of gas-oil systems. However, this laboratory method has consistently posed challenges due to its excessive cost and time requirements. This work focuses on estimating the MMP using numerical simulation of the slim tube experiment. Using a compositional simulator, a Cartesian one-dimensional model was developed to simulate CO2 injection through a slim tube saturated with crude oil. The base case model was validated with existing literature, and sensitivity analyses were performed by adjusting key parameters such as slim tube length, injection rate, reservoir temperature, porosity, and permeability. The study provided insights into the influence of these parameters on MMP value and, more importantly, suggested the optimum values of these parameters for designing and conducting slim tube tests.