Giant fields of Indonesia: play types, geologic factors, and prospectivities of future giant fields
Proceedings, Indonesian Petroleum Association Forty-Third Annual Convention & Exhibition, September 2019
Awang Harun Satyana
Seventeen oil and gas fields of Indonesia are classified as giant fields (estimated ultimate recovery/ EUR/ reserve ≥ 500 MMBO or 3 TCFG) and two as supergiant fields (EUR ≥ 5000 MMBO or 30 TCFG) with total reserves 3P (proven+probable+possible) of 38.17 BBOE. The fields are located in eleven sedimentary basins with the Central Sumatra Basin being the richest basin volumetrically. The supergiant fields: Minas oil field (reserve 3P 5.45 BBO) and Natuna D-Alpha gas field (contingent recoverable resource 3P 46.30 TCF, undeveloped) are the largest oil and gas fields in Southeast Asia.
Globally, the number of giant fields is only 2% of the total fields of all sizes, but they contribute 60% of the production (Merrill and Sternbach –AAPG, 2017) and account for 67 % of the world’s petroleum reserves (Mann et al., 2003). The situation is similar in Indonesia, where most of the oil and gas production has come from 16 producing giant fields. Most of these are very mature, and are presently in production decline. Therefore, the discovery of giant fields is very important for the national petroleum production and reserve. To explore systematically the prospectivities of future giant fields of Indonesia, the play types, geologic factors, and tectonic settings of the existing giant fields are evaluated. The nineteen giantsupergiant fields of Indonesia can be simply grouped into six play types with each reserve 3P as follows:
- Miocene reefal build-ups (four fields: 11,224 MMBOE),
- Miocene inverted structures (five fields: 10,208 MMBOE),
- Miocene deltaic structures (six fields: 8,895 MMBOE),
- Jurassic rifted structures of Australian passive margin (four fields: 6351 MMBOE),
- Pre-Cenozoic fractured basement (one field: 950 MMBOE), and
- Miocene deep-water structures (two fields: 545 MMBOE).
The evaluation provides lessons for exploring the possibility of future giant fields in Indonesia: play type/s that can still account for new giant fields or new play type/s that should be developed. The play types of future giant fields, their locations and petroleum systems are determined by geologic settings, and some areas to focus on are proposed in this study.
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