NITEC conducted a detail field study to evaluate the gas storage potential of a deep depleted oil carbonate reservoir. The study included geology and petrophysics analyses to create a reservoir characterization model for a detailed reservoir simulation study. The simulation model history matched the original depletion period, matching oil, water and gas rates and pressure observation data. Due to the depth and anticipated operating pressure for the storage operations, a compositional model was required to accurately predict the miscible interactions between the gas and remaining oil and the resulting oil production. The results were used to design the liquid handling requirements for the surface facility.