Publications

The necessity of oil and natural gas from fossil energy sources in Indonesia is increasing over time, whereas oil and gas reserves generated from conventional reservoirs are decreasing. To anticipate gas shortages, exploration of unconventional resources is needed. The main focus of the rock formation in this research is the Tertiary Miocene Kasiro Formation. This formation is dominated by Shale and Claystone. Shale characteristic from the megascopic aspect of Tertiary Miocene Kasiro Formation in the research area have fissile structure with soft to hard in hardness scale of shale. Shale characteristic from microscopic aspect based on petrography, SEM (Scanning Electron Magnetic) and XRD (X-Ray Diffraction) show illite as main clay mineral. Other clay minerals such as montmorilonite and kaolinite also can be found as well as some important mineral like quartz, chlorite, biotite, alunite and diaspore. Shale diagenesis rate of the Tertiary Miocene Kasiro Formation is defined based on the presence of some clay mineral like illite, kaolinite and montmorillonite. Based on the result of SEM and XRD analyses, the shale diagenesis in the research area can be classified as early mesodiagenesis. The diagenesis rate also can show that oil maturity in the Kasiro shale can be classified as immature to semi mature. Based on the shale characteristic, the Kasiro shale was deposited in a weak current mechanism and based on the presence of alginite, the shale was deposited within lacustrine environment. The lacustrine environment have a characteristic of low oxygen rate that can be seen with the presence of mollusk fossil such as viviparous that indicating a fresh water and weak current enviroment.