Publications

Banggai Basin with its productive Miocene objectives in Eastern Sulawesi has positioned as foreland basin since Mio-Pliocene time, when the collision of Banggai-Sula microcontinent and East Sulawesi Ophiolite Belt took place. To the east of the basin there is Sula (Taliabu-Mangole) platform preserving Pre-Cenozoic grabens (Sula Basin). Before the collision, the Banggai-Sula microcontinent drifted to its present area bringing syn-rift Jurassic passive margin siliciclastic sediments and Cretaceous to Miocene syn-drifting carbonates. All of these rocks have been potential to be elements (sources, reservoirs, seals, overburdens) and processes (trap formation, petroleum generation-migration) of petroleum system. Collision of the microcontinent significantly affected all processes of petroleum system. This study is based on geochemical characteristics of oils (bulk properties, isotopes, biomarkers) and gases (carbon and deuterium isotopes) and rock geochemistry of expected Cenozoic and Pre-Cenozoic sources. The study investigates the origins of existing oils and gases in the Banggai-Sula microcontinent. Existing and new data oils and gases from wells, fields, and seeps as well as rock geochemistry of well cuttings and outcrops are examined. This study reveals that all oils in the Banggai Basin are sourced by Early Miocene Tomori carbonates and shaly carbonates (resulting in type “A” oils) and Middle Miocene Matindok shales and calcareous shales (resulting in type “B” oils). As for the gases, isotope data show that gases in the Banggai Basin are products of both thermal cracking of oils and primary gas generation from Miocene source rocks with humic kerogens. No significant evidence of petroleum contribution from Pre-Cenozoic source rocks in the Banggai Basin. However, gas seepages in the Sula Basin are geochemically related to generation from Pre-Cenozoic source rocks deposited in graben areas of offshore Taliabu-Mangole Shelf. This study points towards new directions for further exploration in the Banggai-Sula area, both Cenozoic and Pre-Cenozoic objectives can be exploration targets.