Perpustakaan Digital ITB

This study presents a techno-economic optimization framework for surfactant flooding in a synthetic homogeneous sandstone reservoir with an inverted five-spot pattern, using CMG STARS coupled with CMOST. Injection rate and surfactant concentration (mole fraction) were optimized to maximize Net Present Value (NPV), with Recovery Factor (RF) tracked as a secondary technical indicator. Particle Swarm Optimization (PSO) evaluated 500 scenarios, each assessed economically through a simplified discounted cash flow analysis. The waterflood baseline reached an RF of 21.21% and an NPV of 3.067 MMUSD. The maximized NPV scenario, at 2,823 STBD and a surfactant mole fraction of 0.000215 (0.5 wt%), raised RF to 44.47% and NPV to 3.94 MMUSD. The maximized RF scenario, at 4,844 STBD and 0.000338 mole fraction (0.8 wt%), reached a higher RF of 51.14%, but its NPV dropped to 2.82 MMUSD, below even the waterflood baseline, as the added water and surfactant costs outweighed the extra oil revenue. Maximizing recovery factor therefore does not guarantee higher profitability; the integrated CMG STARS-CMOST- PSO workflow offers a practical basis for selecting surfactant-flooding conditions on economic rather than purely technical grounds.