3D SEISMIC GEOMORPHOLOGY INTERPRETATION OF CENOZOIC CARBONATE SUCCESSION IN OFFSHORE TANIMBAR REGION, EASTERN INDONESIA

摘要

The study area is located in the offshore Tanimbar region of the southern Banda Outer Arc, Eastern Indonesia. The study area comprises the Australian passive margin sequences and the structural framework mainly consists of normal fault to the south and imbricated south verging thin skinned thrust system to the north that were formed by collision between the Banda Arc and the Australian continent. The 3D geomorphology interpretation and structural restoration study revealed the depositional environment of the Cenozoic section in the thrusts where the seismic image is not appropriate for seismic sequence stratigraphy due to complex structure. The paper reveals the paleo-depositional environment and suggests the potential reservoir in the study area. The aggradational succession during the Paleocene to Eocene and upward shallowing succession during the Oligocene to Miocene are observed by the 3D seismic data in the study area. The paleo-depositional environment is interpreted as basinal to slope facies during the Paleocene to Eocene and gradually shift (upward shallowing) to the shelf environment during the Oligocene to Miocene which are consistent with the sedimentology in Abadi gas field. Particularly, the paleo-depositional environment in the Late Miocene is interpreted as shelf interior to the south and shelf edge in the thrust zone to the north. The wide distribution of reefal facies in the frontal thrust were confirmed by 3D geomorphological interpretation and paleo-depositional environment interpretation based on structural restoration study. It is recognized that the new exploration potential in these reefal facies of the Miocene thrust anticline play in the offshore Tanimbar region.