The present work focuses on the effect of reservoir stratification (reservoir with layers of different permeability) on a water flood (immiscible displacement) process. Two-dimensional experiments have been performed on a visualization cell packed with sand particles of different sizes to form layers of different permeabilities. A total of four sets of experiments have been performed with alternate layers of high and low permeability and with combinations of horizontal and vertical wells. Also, the perforation length of the vertical injection well and its location has been varied in this work. The study shows that during the oil saturation process, the oil phase preferentially flows through the high permeability regions irrespective of its location in the cell, which causes difficulty in establishing uniform oil saturation in the sandpack. However, during the water flooding process, the water phase preferentially flows through the low permeability regions leaving significant regions of high permeability layers unswept due to capillary pressure. It is also found that the perforation length of the 11 vertical injection wells and its position has a negligible effect on the flow pattern.