سيده مهلا حسيني

increasing need of production from oil and gas fields is economically due to increasing worldwild demands of oil. Since many important oilfields have reached puberty and the number of new discoveries decrease each year, the use of secondary recovery processes is more urgent. Water flooding is one of the most common secondary recovery methods One of the major problems of water flooding is production of water. Consequently, water breakthrough happens quickly. In this condition, the production of reservoir is not economical. in comparison to conventional flooding, cyclic water Injection produces more oil and less water. cyclic Water injection is performed to produce oil from zone with less permeability that can not be displaced. Studies have shown that oil production is more likely to occur during the period of injector shut-in. In order to achieve maximum oil production from oil fields and less produced water, optimization methods should be used in the process of cyclic water injection. By controlling and optimizing the well parameters, such as production and injection rates, choosing the time to convert the wells, managing and deciding about the conversion of wells, as well as the economic evaluation of the process, one can achieve this goal. In this research, we introduce optimization algorithms and provide an effective way to optimize production or net present value (NPV). In this research, Simulation of two-dimensional and three-dimensional synthetic model, as well as validation and sensitization of the model for the duration of injection and shut-in of the injector is performed in the cyclic flooding method. Then, in the synthetic model, the effect of asynchronism open and shut-in of the injection wells has investigated. The cyclic flooding method for the field model is also performed after coarsening of simulation cells, and has studied the effect of converting the production wells to the injection and vice versa. The results show that the cyclic flooding method in two-dimensional model with two variables (injection time and injection stopping) in waterwet and oilwet reservoirs has increased in NPV value 2.26% and 3.9% respectively. an‎d with three variables (injection time, injection stopping and injection rate) has increased in NPV 0.21% and 0.69% in comparison to conventional flooding. In 3D model with three variables after optimization of both methods, the results showed NPV value in cyclic flooding method in oilwet reservoir has increased 0.68% and in waterwet reservoirs decreased 4.6%. in the effect of asynchronism open and shut-in of the injection wells, has increased NPV value 1.63% in comparison to cyclic flooding in waterwet reservoirs. In the field model, this method has increased NPV value 0.6% in comparison to conventional flooding. In the process of conversion of wells is observed increase in NPV in comparison to cyclic flooding and conventional flooding, 8.33% and 9% respectively. Keywords: cyclic water injection, optimization, Reservoirs Management