رضا آذین

Gas Oil Ratio (GOR) is one of the most important production parameters in oil reservoirs. GOR increase results in increase in gas production and a decrease in oil production which may in turn lead to shutting-in the wells due to being uneconomic. This phenomena also causes other problems such as flaring the produced gas, asphaltene precipitation, and low efficient conventional pumps. In this research, firstly the phase behavior of four fluid samples of two high GOR fields are studied. The model of asphaltene precipitation in one of these fields has been built. This model shows the pressure and temperature range of asphaltene precipitation in this field. The dynamic model of one of these fields has been built in CMG software for proposing scenarios to reduce the producing GOR. The effect of reservoir parameters on the production parameters has been investigated. Based on the sensitivity analysis results, number of parameters such as fracture spacing in i and k direction, matrix permeability in i and k direction, fracture permeability in i, j and k direction, matrix and fracture porosity, water saturation, skin of well 3, 4 and 5, gas oil contact depth, reference depth and reference pressure have been chosen for history matching. The history matching is performed to validate the dynamic model for future forecasts. Six scenarios have been defined such as current production, gas injection, water injection, gas and water injection with two water injection wells, gas and water injection with one water injection well and infill drilling. The results show that the water injection scenario prevents the increase of GOR by maintaining the reservoir pressure and maintain the production for a longer period. The investigations show that the gas injection scenario increases GOR and decreases the final recovery from the reservoir. The infill drilling scenario increases oil production for a short time however, the reservoir pressure drop is very significant and this scenario is not