Perpustakaan Digital ITB

The Low Salinity Water Injection (LSWI) method is a promising Enhanced Oil Recovery technique, as it alters the wettability of reservoir rock and improves oil displacement. However, continuous LSWI requires large volumes of treated water throughout the production life, and the Huff-and-Puff technique offers a cyclic alternative by dividing the injected volume into slugs. This study compares the oil recovery performance of continuous high-salinity waterflooding at 30,000 ppm, continuous LSWI, and cyclic Huff- and-Puff LSWI at matched injected volume through numerical reservoir simulation in tNavigatorTM. The simulator captures wettability alteration through relative permeability shifts toward more water-wet conditions, modeled with the Electrical Double Layer Expansion mechanism and the Jerauld salinity weighting formulation. A sensitivity analysis was conducted on the injection technique, injection salinity (1,000, 9,700, and 15,500 ppm), and slug size (1%, 5%, and 10% of pore volume). The results show that both low-salinity schemes outperform the high-salinity waterflood in all cases and are effectively equivalent on ultimate recovery. The optimum continuous case reaches 24.95% at 1,000 ppm and 10%PV, compared to 23.83% for the baseline and 24.91% for cyclic LSWI at the same condition. The principal distinction is timing. The cyclic injection well contributes production from its first puff, roughly thirteen years before the continuous scheme converts its injector at the largest slug, so oil recovery is delivered earlier at equal ultimate value. Slug size is the dominant parameter, followed by salinity, while the injection technique has the smallest effect. The optimum injection design consists of continuous LSWI at 1,000 ppm and 10%PV, with cyclic LSWI as a practical equivalent. This volume-matched comparison framework can serve as a guideline for selecting between continuous and cyclic LSWI schemes in sandstone reservoirs based on production timing, water supply, and operational priorities rather than ultimate recovery.