Perpustakaan Digital ITB

Enhanced Oil Recovery (EOR) has been developed to maximize oil recovery from reservoirs that still contain significant volumes of unrecovered hydrocarbons after primary and secondary recovery phases. Among the available EOR methods, chemical injection particularly polymer flooding has gained renewed interest due to increasing oil prices and the limited availability of new conventional oil reserves. Polymer flooding works by altering the fluid mobility and improving sweep efficiency through changes in viscosity and flow characteristics, especially in heterogeneous sandstone reservoirs that commonly experience early water breakthrough. Polymer flooding aims to increase the viscosity of injected water by adding polymers such as hydrolyzed polyacrylamide (HPAM), reducing the mobility ratio between displacing and displaced fluids. This method helps in controlling water movement and enhances oil displacement from unswept zones. The effectiveness of polymer flooding is influenced by several parameters including polymer concentration, injection rate, and polymer adsorption. These parameters affect the distribution of polymer in the reservoir and the overall recovery performance, making sensitivity analysis essential to identify optimum design conditions. This study utilizes reservoir simulation with tNavigator software to evaluate the effects of polymer concentration and injection rate using a five-spot injection pattern at the “B” Structure in Field “S.” A total of 15 combinations of scenarios were simulated to assess the recovery factor under various conditions. The optimum case was found at 5000 ppm polymer concentration and 750 stb/day injection rate, achieving the highest recovery factor of 30.87%. Additionally, a further analysis of polymer adsorption was conducted in the best-case scenario using three different adsorption values (50, 150, and 300 ?g/g). The results showed a declining trend in recovery factor as adsorption increases, due to the reduction in effective polymer propagation and sweep efficiency. These findings highlight the importance of incorporating polymer retention behavior into simulation models to ensure realistic predictions and effective design of polymer flooding strategies.