Hydrocarbon reservoirs are changed in their properties during production. In such a way that the reservoir is subjected to a pressure drop over time, and therefore these pressure changes cause changes in properties such as the water-oil and gas-oil contacts in the reservoir. The investigation of these kinds of changes, especially in carbonate reservoirs, which are considered as unconventional reservoirs due to the presence of the fracture networks, seems to be very important. These type of reservoirs, with a high fracture permeability, are faced with a more moderate pressure drop. Also, the transition zones between the fluid contact levels and the oil zone are not formed in this type of reservoirs or have very low thickness, as well. Therefore, the changes in the contact levels directly affect the volume of recoverable oil. As the water-oil contact moves up and the gas-oil contact moves down over time, and also the oil zone gradually gets smaller. In this study, the fluid flow model as well as the static model of one of the carbonate reservoirs of Iran have been developed in the Eclipse and Petrel simulators, respectively, and according to the actual field production scenarios from 1990 to 2017, the changes in the fluids contact levels in the production wells have been investigated. Also, these changes have been compared with a mathematical model. In the following, based on the lowest movement of the oil-water contact level and oil-gas contact level, the optimum field area for the safe well drilling at the future years has been specified. In addition, three new production scenarios have been defined by drilling two new wells in the optimum field area from 2017 to 2037, and the optimum production scenario has been selected based on the production results. Eventually, this optimum production scenario has been investigated and verified based on the changes in the fluids contact levels. Also, the production scenario with two horizontal wells is considered as the optimum production scenario.