BINTUNI BASIN - PAPUA

BINTUNI BASIN, PAPUA

Geographically, Papua is divided into 3 major components, namely the Bird's Head (KB), the bird's neck and the Papuan bird body. The Bintuni Basin is in the Bintuni-West Papua Bay, precisely located in the head-neck part of the bird.

Regional geological map of Bird's Head (KB) (Shawwal, 2010)

The Bintuni Basin is a basin with an area of ​​± 30,000 km2 which tends to be north-south trending with the Late Tertiary age which developed rapidly during the process of lifting the LFB to the east and Kemum block from the north. This basin to the east is bordered by the Arguni Fault, in front of it is LFB which consists of Mesozoic clastic rocks and tertiary-aged limestones which experience folding and braking. To the west of this basin is characterized by structural elevations, namely the Sekak Mountains which extend to the North, in the north there is the Ayamaru plateau which separates the Bintuni Basin from the Salawati Basin which produces petroleum. In the south, the Bintuni Basin is limited by the Tarera-Aiduna Fault, this fault is parallel to the Sorong Fault located north of KB. Both of these faults are the main faults in the West Papua area (Anonim, 2014).

As a basin around the collision between three plates, namely the Eurasian Glue, the Australian Indian Plate, and the Pacific Plate, the Bintuni Basin has a highly complex tectonic history. According to Lemigas (2009), tectonic episodes and geological structures that have evolved cannot be separated from the four large-scale tectonics that occur in Eastern Indonesia and Australia, namely:

• Rifting in the Early Jurassic along the northern boundary of the Australian Plate (Island of Papua New Guinea).
• Rifting Early Jurassic along the northwest of Autralia Expansions including the NW shelf rift.
• Neogenous collections between the Pacific Plate and the Australian Plate, and subduction in the Trench in New Guinea that produces Papua and Lengguru.
• Neogene colosiation between the Banda Line and the Australian Plate that forms the Kumawa-Onin-Misool Islands Line.

Sketch map of the Tectonic Elements of the Bird's Head Area of ​​West Papua (Lemigas, 2005 in Lemigas, 2009).

All these tectonic episodes are implicated in the complexity of structural arrangements in western Papua, especially in the Lengguru and Babo areas on the Neck of the Bird's Head. According to Lemigas (2005, in Lemigas, 2009), the pattern of geological structural elements in the Bintuni Basin is relatively the same as that which generally exists in the Bird's Head area, namely:

• Lineage with east-west to northwest-southeast direction represented by the fault system goes up Misool-Onin.
• Line with the northwest-southeast direction.
• East-west direction associated with the Sorong Fault.
• Lineage with north-south-southeast to north-south direction in the form of Perem's buried structure.
• North-south direction line that is associated with the Leng-guru folding route.

REGIONAL STRATIGRAPHY

Pratersier stratigraphy The Bintuni Basin is inseparable from the general Bird Head stratigraphy. According to LEMIGAS (2009), the oldest rock deposited was the Kemum Formation of Silur age until Devon, which over time has been very deformed. The Aifam group sediments then hitched on top of it in disagreement. The group includes the Aimau Formation which is based on Carbon, the Aifat Formation which is of Carbon age to Perem, and the Ainim Formation which is of the Late Perem to Early Trias. Tipuma Formation that is aged Trias to Jurassic Initially overlaps inconsistently Ainim Formation. The Kambelangan group deposits then overlap the Tipuma Formation in harmony. The Kambelangan group includes the Kambelan gan Bawah and Jass Formations. In these groups, the Lower Kambelangan Formation that is Middle to Late Jurassic age is overlapped unconformably by the Jass Formation which is of Late Cretaceous age. Above the Jass Formation are Tertiary-aged sediments

Pratersier sediments that have the potential to become an essential element of the oil system, namely sandstones of the Tipuma and Kambelangan Bawah Formations as reservoirs, and shale for Ainim, Tipuma, Kembelangan Bawah, and Jass as source rock

West Papua's Bird's Head Stratigraphy

References:

• Ibrahim, Anditya, Satyana, A.H., Pudyo, N., dan Sunjana, E.S. 2006 Hydrocarbon Discovery in the Frontier Area at Eastern Indonesia: Lessons for Future Discoveries BPMIGAS, Jakarta, Indonesia. AAPG International Conference and Exhibition, Perth, West Australia.
• Lemigas, 2009. Paleogeografi dan Potensi HC Cekungan Pratersier Daerah Kepala Burung. Pro­gram Penelitian dan Pengembangan Teknologi Eksplorasi Migas. Lemigas Jakarta.
• Panuju et., al.,2012, Zonasi Biostratigrafi Nanoplankton Berumur Coniacian - Maastrichtian (Kapur Akhir) Cekungan Bintuni, Kepala Burung, Papua, 1Exploration Division, PPPTMGB “LEMIGAS” Jakarta Sekretariat Badan Litbang ESDM