A successful water flooding project requires continuous surveillance and updated studies. The use of moder practices is also essential to achieve maximum oil recovery. Field 'X' lies in the Western Desert of Egypt. Although the fiel employs water flooding as a secondary recovery mechanism, it suffers from low oil recovery, low sweep efficiency and water's production rates. In 2014, a field development plan was issued with a target recovery factor of 30% using water flooding. However, actual production has significantly underperformed initial forecasts, motivating a re plan. In particular, it was considered necessary to revisit the underlying geologic concept and how this was incorporated into flow simulation forecasts. The aim was to maximize the oil recovery factor before resorting to an expensive tertiary recovery plan; especially, under current low oil prices. This paper discusses the value of updating both static and dynamic models to better incorporate uncertainty associated with facies distribution. It also demonstrates the use of streamline simulation to reallocate water injection rates and determining the role of facies communication in improving the areal sweep efficiency. The new injection scheme is supported by the updated dynamic modelling study and added an incremental reserve of 6.5% and unlocked 28% of the oil in place in the field.