Perpustakaan Digital ITB

Peripheral water injection has been conducted for over 40 years in Z6-5 reservoir in the Mahakam Delta. The injection has successfully supported the reservoir pressure just enough to maintain an economically acceptable production trend. In 2017, the company initiated screening to apply waterflooding strategies in this mature reservoir. To support this study, static-dynamic reservoir simulation is needed. However, the uncertainties remain large due to the model not being history matched. Therefore, at the onset of this study, 32 subsurface parameters that may impact the reservoir performance were identified. Experimental Design using Assisted History Matching provided multiple history-matched models and ranked the most significant uncertainties. Particle Swarm Optimization is then performed to minimize the objective functions of pressure, oil total, gas total, and water total mismatch. It was shown by the generated Pareto Chart that considerable uncertainty exists in the simulation. This sensitivity analysis serves as a reference for adjustments to be made in the following manual history matching. To maximize the ultimate recovery, several development strategies were constructed. Forecast shows that the best scenario may add 5.5% to the recovery factor. The results conclude that waterflooding in this reservoir is restricted by high water saturation and low oil moveable oil concentration.