The Akimeugah Basin - Papua

The Akimeugah Basin - Papua

The Akimeugah Basin is located north of the southern Papuan basement high (Merauke Ridge) which separates it from the Arafura Basin to the south. This basin Judging from its association with surrounding basins, the akimeugah basin is associated with basins that have produced hydro-coal in the West Papua Basin and Australian basins. From tracing various journals and articles, the geochemical literature will provide an overview of the active host rocks in the area.

 

The index map of the Akimeugah and Sahul Basin is based on the Indonesian Sediment Basin Map (Badan Geologi, 2009).

The Akimeugah Basin begins as a passive margin, which is a basin formed by rifting on the northern edge of the Australian continent at the edge of this bank, experiencing cracking due to the part of the northern part of the mass that wants to escape and move from Australia. In this crack a horst and graben are formed which in the graben is deposited sediment of Paleozoic and Mesozoic synrifting. Then, when this part is separated and away from Australia (drifting) sediment drifting is deposited which is generally in the form of shale or limestone, this event occurs until Paleogene.

 

Tectonic maps and cross sections of the foreland basin

Cross section of the foreland basin in eastern Indonesia

At the age of Neogen, Akimeugah collided with the Central Range of Papua (Back of Papua). Since then the type of foreland basin Akimeugah. Passive margin of the Paleozoic-Neogene is bent into the lower Banda route and Central Range. Then at the front of the buckling (foredeep) deposited molassic sediments which are erosional products from nearby heights. However, and burial by the sedimentary molasses part of the passive margin, Akimeugah has ripened Paleozoic, Mesozoic, or Paleogene host rock in the graben then the hydrocarbon migration will move flips from foredeep to the forebulge (the direction in the direction of the passive margin that is not bent like foredeep) laterally, or moves vertically towards the immobilization deformation zone in the impact area. The main controls of the Akimeugah basin are rifting and drifting in the Mesozoic-Paleogene Paleozoicum, and collisions on Neogene (Awang Satyana, in Sabarnas Agus 2011)

  

Stratigraphy of the Akimeugah Basin

The Akimeugah Basin consists of pre-cambrian-tertiary deposits. The basic rock consists of Gabro rocks aged pre-cambrian and Metamorphic rocks. Followed by the deposition of the Permian Dolomite Modio formation and the Aiduna Formation which were deposited incongruously. Then it was harmoniously deposited on top of Mesozoic clastic formations (Tipuma, Kopai, Woniwogi, Piniya and Ekmai Formations), and some carbonate coatings locally. Above the Ekmai Formation, overlaid by clastic and limestone Paleocene-Miocene age (Waripi, Lower Yawee, Adi Members, and Upper Yawee) are out of tune. The last deposition was the final claystone clay from the late Miocene to Plio-Pleistocene and the uncoated local carbonate, the Buru Formation.

The petroleum system that works in the Akimeugah Basin is in the Kozelang Group, which is Mesozoic. The auction group consists of four formations, namely: Kopai Formation, Woniwogi Formation, Piniya Formation, and Ekmai Formation. The Kopai Formation is source rock with kerogen types II and III, Ro is greater than 0.6%, and TOC ranges from 1 - 10% on Sahul Exposure. The Woniwogi Formation is a reservoir rock with porosity ranging from 12-14% with permeability between 200 - 500 mD (Meizarwin, 2003). The Piniya Formation is a covering rock composed of claystone with a thickness of up to 900 meters (Panggabean and Hakim, 1986). The Ekmai Formation is a reservoir rock in the Bayu - Undan Field, but in the Akimeugah Basin this rock is not a good reservoir rock.

Australia and Papua New Guinea have produced oil and gas from the same basin system, namely the foreland basin, the same reservoir rock, which is the Middle Jurassic - Cretaceous sandstone, and may conclude the same petroleum system. Indonesia's declining oil and gas reserves are a shared responsibility, moreover geologists are the key to finding that potential. With new concepts, more complete data, and a deeper interpretation of existing data, the potential for oil and gas reserves in the Akimeugah Basin can be found. The hope of oil and gas is in the East of Indonesia, precisely in the Akimeugah Basin of Papua Island.

Reference:

• Satyana, A.H. (2013) : Exploring & producing Petroleum in Eastern Indonesia: Update knowledge & Recent Trends. Guest Lecture Ikatan Alumni Teknik Geofisika ITB.
• Satyana, A.H., Damayanti, S., Armandita, C. (2012) : Tectonics, Stratigraphy, and Geochemistry of The Makassar Straits: Recent Updates from Exploring Offshore West Sulawesi, Opportunities and Risks. Proceedings Indonesian Petroleum Association 36th Annual Convention.
• Satyana, A.H., Damayanti, S., Armandita, C. (2012) : Tectonics, Stratigraphy, and Geochemistry of The Makassar Straits: Recent Updates from Exploring Offshore West Sulawesi, Opportunities and Risks. Proceedings Indonesian Petroleum Association 36th Annual Convention.
• Situmorang, B. (1982) : The Formation of The Makassar Basin as Determined from Subsidence Curves. Proceedings Indonesian Petroleum Association 11th Annual Convention, 83-107.
• https://dzulfadlib.wordpress.com/tag/lapangan-minyak/
• http://geomagz.geologi.esdm.go.id/cekungan-akimeugah-dan-sahul-harapan-baru-penemuan-migas/