Upper Bahariya reservoir is one of the big productive reservoirs in the Western Desert (Egypt). It is characterized by high degree of heterogeneity. So, it is very important to characterize it accurately for improving its recoverable oil. Different tools were used to accomplish this task. These tools include Dykstra-Parsons coefficient, Lorenz coefficient, well correlation, hydraulic flow units, relative permeability and capillary pressure. Dykstra-Parsons coefficient (permeability variation factor) and Lorenz coefficient were determined for Upper Bahariya reservoir and found to be 0.86 & 0.92 respectively. This reveals that this reservoir is extremely heterogeneous. These results are proportionated with the pressure readings and the open hole logging format. The hydraulic flow unit’s reservoir technique showed the reservoir can be divided into nine flow units. The relative permeability curves of the reservoir indicated that it is a water wet system while the capillary pressure curve looks like a transition zone due to its high heterogeneity and high connate water saturation.