Perpustakaan Digital ITB

The Field MS is one of the largest oil field in Indonesia, situated within the Central Sumatra Basin. The field started production in 1952 and has yielded a total of 4.5 BSTB of oil through both primary and secondary recovery development. With an estimated remaining oil reserve of 4.5 BSTB oil, a tertiary recovery development strategy through CEOR (Chemical Enhanced Oil Recovery) project has been developed since the 2000s to recover the remaining residual oil. This study aims to identify the actual PIR that generated while chemical flooding system applied in the Field MS, compare the oil recovery at different production-injection ratio (PIR) set in chemical injection project in the Field MS using an inverted 7-spot well pattern and evaluate the economic aspects of the oil recovery for each Production-Injection Ratio scenario through several parameters. This study was conducted using CMG-STARS to simulate the reservoir to obtain production and injection rates over the time. Two field development scenarios were conducted starting with waterflood until the economic limit was reached, followed by the designed chemical flooding. The production-injection ratio was varied between 0.5, 1, 1.5 and 2 with the injection rate is set constant of 4500 barrels per day to compare the cumulative oil produced by each scenario. The PIR setting of 0.5 could not be achieved, due to the pressure constraint. The pressure builds up rapidly due the double volume of injection compared to production. The other PIR variations showed PIR values that were as expected. The final simulation results showed that during chemical flooding and post flush, a PIR value of 0.5 gave the highest cumulative oil production of 129617 barrels oil, showing 23% of incremental oil recovery compared to waterflood, while during the combined scenario (waterflood and chemical flooding), a PIR value of 2 gave the highest cumulative oil production of 673,720 barrels of oil. A simple economic evaluation was also conducted, which led to the conclusion that the highest cumulative oil production also provided the highest revenue.