Perpustakaan Digital ITB

as a potential way to improve oil production. CO2 huff-n-puff project in “M” Field was a pioneer of CO2 injection in Indonesia and it is also hoped to lead the higher scale of Indonesia’s CO2-EOR. This potential has brought the strong needs of studies to perform method in monitoring the reservoir performance of CO2 injection. One of the tools to analyze the CO2 performance is material balance equation (MBE), which is capable to produce a relatively reliable result with its simplicity compared to reservoir simulation. This paper applies the extended MBE for CO2 flooding by Tian and Zhao (2004) to investigate the reservoir performance of “M” Field during the CO2 huff-n-puff injection. The actual PVT, fluid, rock and CO2 properties are utilized or obtained from correlations before the output variables are solved for monitoring and evaluation purpose. CO2 injection performance is monitored by analyzing the solved variables, which includes the amount, percentage, and ratio of CO2 distribution in reservoir. It is found that the injected CO2 in “M” Field dissolves easier in reservoir oil compared to in water or remain in gas phase during the injection time. However, with the greater amount of CO2 injected all the time, the ability of CO2 to be dissolved in oil decreases. Overall CO2 huff-n-puff scenario in “M” Field performed positive result, as approximately 75% of injected CO2 dissolves in reservoir oil. The study shows that extended MBE model for CO2 flooding can also be applied to observe the CO2 distribution for huff-n-puff scenario. The extended MBE model can be further utilized for other purposes, such as injection scenario optimization.