Surface geological investigation as the initial stage of hydrocarbon exploration in Kei Besar Island, Southern Maluku

Abstract

Kei Islands are known to have hydrocarbon potentials in shallow rock layers, trapped by folds and faults. This potential is characterized by the amount of gas seepage found in Kei Kecil, Kei Besar and Tayandu Island. The study was conducted in central and southern part of Kei Besar Island through outcrop observations and stratigraphic measurements aim to recognize the physical characteristics of rock. Kei Besar Island located in the easternmost part of Australian continental passive margin separated by the extension of Aru Through. Digital Elevation Model of Kei Besar Island shows that the northern part of research area has a steeper morphology than the southern. The stratigraphic characteristic in the central part of research area dominated by clastic limestone showing a shallowing-up stacking pattern. While in the southern part, the lithology dominated by coralline limestone contains many fragments of coral and large foraminifera. Stratigraphic analysis shows that lithology in the study area was formed in carbonate submarine fan which formed Elat Formation. This formation underlained by shallow carbonate rock which contain large foraminifera from Tamangil Formation. Tamangil Formation interfingered with lower part of Weduar Formation. Based on the analysis of surface data above, concluded that subsurface exploration is necessary to reconstruct the petroleum system in research area.

Nannofossil Biostratigraphy of Elat Formation, Kei Besar Island, Southeast Maluku

“…The stratigraphy of Kei Besar Island consists mainly of middle Eocene to Quaternary -aged limestones. The Elat formation, which is the main constituent rock, is a pelagic or hemi pelagic carbonate deposit that composed by the intercalation of calcarenite and calcilutite [2].…”

“…The lithological variations of this formation reflects changes in the environment setting throughout their deposition, that occurred in the distal continental slope and the outer fansub marine fan [3,2] within the neritic bathymetric zone (shallow marine) [1] (Figure 1). 3.…”

“…Kei Besar Island is mainly composed by intercalation of calcarenite marl and marl and the Elat Formation has an Eocene age deposit in neritic zone [1], or calcarenite and calcilutite of the Elat Formation [2] . The Elat Formation is a pelagic or hemi pelagic carbonate deposit [3] .…”

Litofasies Dan Lingkungan Pengendapan Pada Formasi Elat, Kecamatan Kei Besar, KabupatenMALUKU TENGGARA, MALUKU

“…Secara geologi daerah Kei besar didominasi oleh batuan Kalkarenit dan Napal yang beragam (Achdan, A. dan Turkandi, 1994). Formasi Elat, yang merupakan formasi di Kei Besar, dimana penelitian dilakukan ditandai dengan gas-gas yang muncul ke permukaan melalui batuan formasi tersebut yang dapat menjadikan Formasi Elat sebagai salah satu bagian dari petroleum system (Kurniasih, Qadaryati, & Setyawan, 2019).…”

Natural Radionuclides Determination and Radiological Hazard Assessments in Soil from Tual and Kei Islands, Indonesia

“…Kei Besar is a narrow and mountainous island, stretching about 85 kilometers from southwest to northeast, and reaching elevations over 800 meters and geologically older than others. Limestone dominates on most of the by fringing reefs surrounded islands [21,22]. Soil samples were collected from Tual, Kei Kecil and Kei Besar islands at the flat, open and undisturbed area.…”