Perpustakaan Digital ITB

Water injection is commonly used as a secondary recovery method to maintain reservoir pressure and improve oil recovery. This study compares oil-zone injection and water-zone/aquifer injection under three injection patterns: Five-Spot, Direct Line Drive, and Staggered Line Drive with ADS well production. The simulation was conducted using tNavigator with a black-oil model for 10 years, consisting of 5 years of primary recovery followed by 5 years of water injection at 300 STB/day. The performance was evaluated using cumulative oil production, recovery factor, average reservoir pressure, and watercut. The results show that water-zone injection performs better than oil-zone injection in all patterns. In the Five-Spot pattern, oil-zone and water-zone injection give 470.355 MSTB vs 503.995 MSTB, 1.147% vs 1.228% RF, and 0.831 vs 0.143 watercut, respectively. In the Direct Line Drive pattern, the results are 741.605 MSTB vs 846.859 MSTB, 1.809% vs 2.064% RF, and 0.837 vs 0.156 watercut. In the Staggered Line Drive pattern, the results are 801.033 MSTB vs 898.293 MSTB, 1.953% vs 2.189% RF, and 0.835 vs 0.156 watercut. These results indicate that water-zone injection gives higher oil recovery and much lower watercut because it reduces direct water breakthrough. Under the current simulation configuration, Staggered Line Drive with water- zone injection gives the best performance and is recommended for further evaluation with normalized well configurations and sensitivity analysis.