Perpustakaan Digital ITB

Waterflooding is widely applied to maintain reservoir pressure, yet a substantial portion of oil remains trapped after its application. Low-salinity water injection (LSWI) is an enhanced oil recovery method that reduces oil trapping by altering rock wettability through brine–rock–fluid interactions. In LSWI simulation, a salinity weighting factor is required to interpolate relative permeability between high-salinity and lowsalinity curves, yet a linear function is commonly assumed by default without further validation. This study investigates the effect of salinity weighting factor function, injected water salinity, and reservoir permeability on oil recovery through a three-dimensional reservoir simulation built in tNavigator. The model represents a synthetic 25×25×25 grid reservoir developed under a 5-spot pattern with four injectors and one producer, with relative permeability at each salinity level calculated using the fitted Khosravi et al. (2024) correlation. Six weighting factor functions were tested: Linear, High Salinity, Low Salinity, Abrupt, Quadratic, and Square Root. The simulation results show that the choice of salinity weighting function can alter predicted recovery factor by up to 14%. The recovery factor increases as the injected-water salinity decreases from 9000 ppm to 1800 ppm, while water cut shows the opposite trend. Reservoir permeability improves recovery factor significantly from low to medium permeability, but only marginally from medium to high permeability, as water coning at high permeability accelerates formation water breakthrough and shortens the duration of the wettability alteration effect. These findings indicate that both the salinity weighting factor function and reservoir permeabilit