Publications

The Tokala area is located in the southern extension of the onshore Matindok block. This area is less explored than the northern part of the block due to seismic data limitation and undefined geological model. Proven petroleum system plays for the northern area are related to collisional tectonic between East Sulawesi Ophiolite (ESO) and Banggai-Sula block, as part of Australian fragment. In 2016, Pertamina EP revisited the geological model of the southern extension of the Matindok block based on Villeneuve et al. (2000), which mentioned about two continental block collision in the eastern arm Sulawesi, which are Tokala and Banggai-Sula blocks. The interpretation performed of a NW-SE 2D composite seismic line passing through the Dongkala-1 and Tolo-1 wells, showed possibility of the Tokala and Banggai-Sula blocks to be sub-thrusted beneath ophiolite. Residual gravity anomaly also shows a new depocentre that differs from the proven kitchen area beneath Batui Thrust Mountain to the North. We interprete that Mesozoic sediments of the Tokala Block are deposited in this new southern depocenter area. Based on previous geological mapping, shale and coal facies of the Triassic Tokala Fm. can be expected as potential source rock. Reservoir quality, trap integrity and seal effectiveness remain undefined. New biomarker data derived from an oil seep identified in the Menyoe Area of the Tokala Mountain during geological field mapping, show small value of oleanane index, suggesting a Mesozoic origin. There have been several oil seeps found in eastern Sulawesi but showing high oleanane index and suggesting a Cenozoic origin. Oil to source correlation between the Menyoe oil seep and extract organic matter of shale facies from the Triassic Tokala Fm show positive correlation in term of oleanane index and C29/C30 Hopane ratio. These evidences have opened new opportunity to further explore for a Mesozoic petroleum system in the southern part of the Matindok Block.