Mehdi Safari - Petroleum University of Technology, Ahwaz, Iran

A naturally fractured reservoir may be divided vertically into several zones, i.e. gas cap, gas invaded, undersaturated oil, water invaded, andaquifer. Gravity drainage is the main oil producing mechanism in gas invaded zone. Depending on the wettability of the reservoir rock, the main recoverymechanism in water invaded zone will be gravity drainage or imbibition for oil wet or water wet rock, respectively. When production from a reservoir starts after awhile, the production will decrease because of reservoir depletion. To enhance the final recovery there are some scenarios, one of them is waterinjection. Water injection has been the most used recovery method in petroleum industries due to its advantages. The injected water displaces oil fromporous media to producing wells and maintains the reservoir pressure above of saturation pressure, increasing the recovery process efficiently. One ofimportant variable is injection rate that influence the water injection performance, therefore by simulating the reservoir with different injection rate we could obtain the proper one for reservoir development. The goal of this work is to study the impact ofwater injection rate on the reservoir performance andsimulate the water injection performance in reservoir scale. This work is a case study on Azadegan oil reservoir. This work is done on investigation of water injection in sector A of Azadegan oil reservoir that it has a dual porosity manner. Water injection simulations wereperformed at different rates. Before any injections the plateau time is about 5000 days. After putting the injection wells and applies the rates it is observed that the plateau time is increased. Higher water injection rates results in higher oil production sowater injection is suitable for this dual porosity case. Because water moves through fractures quickly and so capillary imbibition process can help push the oil to producing well.