Publications

The offshore area north of the Banggai-Sula Islands east of Sulawesi is one of the most under-explored areas in eastern Indonesia. Study of recently acquired 2D seismic data and high resolution multibeam bathymetry allows a better understanding of this structurally complex area. The identification of hydrocarbon seeps on the sea bottom has significantly reduced the thermogenic charge risk in the basin. Geological structures observed in the area show dramatic differences with what have beenpreviously interpreted: no offshore continuation of the north dipping Batui thrust, no evidence of the NW trending steep fault of Greyhound Strait fault, and no westward continuation of the Sorong fault observed in the area. New observed structures are dextral fault system in the west and a wedge of highly deformed sediments in the east. Tectonic evolution which formed geological structures in this area is related with the west-northwest drifting of the Banggai-Sula microcontinent from northern Australia which then collided with the East arm of Sulawesi, southward gravitational flow of materials from the highly elevated Molucca Sea collision zone between Sangihe arc with Halmahera arc, and possibly the NW-SE opening of the Gorontalo Basin. On the backscatter data of the seabed multibeam, numerous areas of high anomalous backscatter are present and correspond with locations of fault lineaments, mud volcanoes, outcrops and location of debris materials deposited due to gravitational slide within north dipping margin of the microcontinent. In number of locations, possible hydrocarbon charges have been detected based on geochemical analyses of the piston cores deployed into the seabed. Gas shows within the fractured Banggai granite basement has been recorded in well Loku-1 in the north dipping, tilted margin of the microcontinent. The reservoir is overlain by the immature-mature Buya shale which acts as both source and seal.