The New Insight of Arafura Basin Petroleum System



Arafura Basin, which is administratively located in Southeastern edge of Indonesia and also extends to the Northern of Australia, yields a potential in yielding hydrocarbons. Flanked to the East by Sahul Basin and to the west by Palung Aru Basin, both are frontier basins, makes the Arafura Basin joins the series of Eastern Indonesia frontier basin. Exploration activity of Arafura Basin in Indonesia region was first commenced in 2006 as Conoco Phillips gained an interest there then later acquired Arafura Sea PSC in 2008. Further south in Australia, exploration activity was commenced earlier. Several wells were drilled and hydrocarbons indications were encountered mainly from the Paleozoic succession. These are the evidences that active petroleum systems lies within the Arafura Basin. As a part of Eastern Indonesia sedimentary basin, Arafura Basin comprises Paleozoic-Mesozoic sedimentary rocks and Proterozoic metasediments and igneous rocks may act as the basement of this basin. So, Paleozoic petroleum systems were expected to occur in Arafura Basin. Questions arise regarding the petroleum system elements and processes, including the time of generation and migration from source rock to reservoir and also the trapping mechanism which become the main risks to be assessed in this basin.
Cambrian-Ordovician and Devonian sediments are believed to be the main source rock for overlying reservoir sediments, where hydrocarbons indications were encountered from Devonian and Permo-Carboniferous clastics and Ordovician-Cambrian shallow marine limestones and dolomites. Those reservoirs properties are showing poor quality of porosity and permeability. Early-Late Cretaceous mudstone unit and mudstone intervals within Paleozoic section are the regional seal and intraformational seals respectively for structural and stratigraphic combination traps in Arafura Basin. Yet the timing of hydrocarbons generation and migration, in relation to trap formation and reservoir deposition, is the key risk factor in Arafura Basin (modified Earl, 2006).


Authors : Wendra Akhmad Faridsyah, Heri Setiawan