This paper presents the implementation of pattern water flood in a very complex field in Romania. It's a multilayer formation with thin 2-5 m highly permeable (up to 2 Darcy) unconsolidated sands and unknown fluid contacts. Additionally high mobility ratio (around 50) and unfavourable rock wettability complicate the water flooding process. Project considered different injection schemes like peripheral, line drive and pattern. Integrated approach includes depositional environment analysis, 3D seismic interpretation, acquisition of complex log to investigate current oil saturation, field injectivity tests, pilot water injection and intensive surveillance plan. Water injection is part of field redevelopment plan and will increase recovery factor by 7.3%.