Modeling of Cyclic Water Injection, East Unity Oil Field – Sudan

Abstract

In this study cyclic water flooding method using numerical model was tested in a middle to a high permeability zones and compared with the actual water injection method used in the field. The study was carried out on a Sudanese oil reservoir which resulted of fluvial and lacustrine deposition. The field is a highly complex anticline with major flanking faults extended to east and west. The reservoir highly heterogeneous is characterized by mid to high porosity and permeability. The actual water injection method used in East Unity is a continuous method (twelve months per year) through a three injection wells. In this study, cyclic water injection was evaluated in Aradeiba formation simulating several cyclic water injection scenarios by "injection/no injection" time ratios such as 2:1, 1:1, and 1:2. Improved sweep, accelerated oil production, and reduced water-cut were the main advantages that could be obtained from cyclic waterflooding. The total oil production was predicted to show an increase of 2% from the targeted reservoirs after 10 years, while the cumulative water injection is expected to decrease by 15 – 18%. However, 28.22% of the oil in the area can be produced during 10 years using the scenario 2:1 which is expected to result in an increase of 2.54% compared with the water injection method used.