IPA17-190-SG
PROCEEDINGS, INDONESIAN PETROLEOUM ASSOCIATION
Forty-First Annual Convention & Exhibition, May 2017
GEOLOGICAL OBSERVATION ON KABAENA ISLAND, SOUTHEAST SULAWESI: AN IMPLICATION OF HYDROCARBON OCCURRENCE IN A FRONTIER AREA BASED ON OUTCROP STUDY
Iyan Fadhlurrohman*
Aprila Fitriani Parma*
Citra Fitriani*
ABSTRACT
Kabaena Island, located in Southeast Sulawesi province, has a complex tectonic history. Field geological mapping conducted by University of Hasanuddin students indicates that Kabaena Island was formed by the convergence movement between microcontinent plates with oceanic plates that are composed of complex ophiolite and metamorphic rocks.
The purpose of this paper is to explain the geological conditions in Kabena Island and the potential occurrence of hydrocarbons based on outcrop model and petrographic analysis. The results of petrographic analysis from rock samples in the study area indicate ultramafic rocks contain Ca-Rich and Mg-Rich Pyroxene and Olivine, while the metamorphic rocks have occurrences of Chlorite, Amphibolite and Sericite. A limestone unit that has undergone metamorphism to be mostly a marble show sufficient fracture porosity. Meanwhile the black shale rocks which from limestone units locally occurred on this island, has undergone a low-level metamorphic processes to slate.
Result from outcrop and petrography analysis, those samples are that the Matano Formation has the highest potential to be a source rock and reservoir rock in form of black shale that is mature but low Total Organic Carbon, and a fractured limestone that has porosity but limited permeability due to re-calcification processes and low grade metamorphism.
Tectonic conditions in the study area indicate the occurrence of thrust faults of ultramafic rocks onto the microcontinent. Analysis of this study also indicate that strike slip faulting occurs within the study area and can be correlated with the presence of gas seepage points in the limestone unit.
Keywords: Kabaena Island, Outcrop, Petrography, Reservoir Rock, Source Rock
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