Perpustakaan Digital ITB

The declining production of late-life assets poses as one of the most significant challenges in Indonesia's oil and gas industry. In 2019, 46% of the oil and gas working areas within Indonesia are mature fields. In addition, 90% of Indonesia’s production comes from mature field. Thus, mature fields remain the backbone of the industry. They offer a significant advantage in compared to exploring new reserves to be exploited. However, most “highly detectable” hydrocarbon zones are already hard to find in mature fields. Therefore, it is important to generate creative strategies to overcome such challenge. The study revolves around “X” Field which has been producing since 2001, penetrating to five formations (D, BK, BN, MN, and PM) possessing a total of 16 reservoirs, through 13 producing wells. The “X” Field has a declining production rate, with current recovery factor of 32% and original oil in place of 14.7 MMBO. The producing zones have initially focused on zones where log readings show high reservoir quality, and the availability of such zones is diminishing. Therefore, detecting bypassed oil zones can prolong the field’s life. Given the abundance of clay minerals of glauconite and kaolinite, this study approaches the challenge through redetermining new resistivity cut-off value, through log and swab data utilization. The selected zone analysis comprises of initial fluid rate prediction, and further filtered by using critical fluid rate calculation as a constraint to prevent an early breakthrough due to water coning. Bournazel and Jeanson method was deployed to calculate the said constraint. From the filtered interest zones, each well is ranked based on cumulative oil production determined through decline curve analysis. The well with the highest cumulative oil production is identified as the most economical for intervention. The study found that TM-11 Well is the optimal economic choice, delivering a cumulative oil production of 17.2 Mbbl and an initial rate of 62 BOPD with a 95% water cut. This method offers a promising approach to extending the life of mature fields in Indonesia.