Polymer flooding is the evolution of conventional water flooding technique. Instead of using just water to displace oil, polymer is used as an alternative to injection water. The polymer introduced to the injection water affects the viscosity of displaced fluid and hence decreases mobility ratio, improves stratification efficiencies and frontal saturations. The relative flow rates of water and oil are altered by the polymer solution, sweeping larger area of the reservoir and; therefore, more oil is in contact with the polymer solution and displaced to the production well. One of the principal purpose of this research is to examine the efficiency of polymer flooding in an oilfield by performing sensitivity analysis, which includes altering injection timing, polymer concentration, injection rate, injection layer, injection period and well configurations in a Western Australian oilfield. Also, water flooding is to be conducted as a base case to compare the efficiency of oil recovery for polymer flooding. A 7*7*6 box model was built and all the reservoir fluid data were analyzed using Computer Modeling Group (STARS). The results show that there is a slight increase in oil recovery (1.72%) after polymer is injected. However, by changing the well configurations, a significant increment of 12.46% of oil recovery is observed