STUDI GEOKIMIA ORGANIK BATUAN INDUK BERUMUR MESOZOIKUM DAN KENOZOIKUM SERTA KORELASINYA DENGAN MINYAK BUMI DAN GAS BUMI DI CEKUNGAN BANGGAI, PROVINSI SULAWESI TENGAH

• Main Author: Fahruddin, Achmad
• Format: Theses
• Language: Indonesia
• Subjects: Geologi, hidrologi & meteorologi
• Online Access: https://digilib.itb.ac.id/gdl/view/80188
• Institution: Institut Teknologi Bandung

the petroleum systems of the Banggai Basin by conducting organic geochemical studies of Mesozoic and Cenozoic-aged source rock samples and their correlation with the oil and gas that are present in the Banggai Basin. This thesis used source rock geochemical data of 1.290 samples from nine formations of Triassic to Pliocene age, 20 oil samples, and 21 natural gas samples. Sedimentary rock samples were then selected based on the total organic carbon (TOC) value of 1% and S2 of 5 mg HC/g of source rock to maintain data quality, resulting in 73 rock geochemical data. Oil and gas geochemical data came from seepages and wells in the Tiaka, Senoro, Donggi, and Matindok fields. Data were analyzed qualitatively and quantitatively to determine the nature and origin of oil and gas. Multivariate statistical analysis of oil geochemical data was also conducted using the hierarchical clustering analysis (HCA) method. Source rock analyses have been conducted on 73 rock geochemical data from nine formations, covering the quality, quantity, and maturity of the source rock. There are two Cenozoic age rock formations (Matindok Formation and Tomori Formation) and one Mesozoic age rock formation (Tokala Formation) that are the effective source rocks. There are two rock formations of Mesozoic age, which are the the Nambo/Buya Formation and the Bobong Formation which are possible source rocks. Biomarker analysis of the Matindok Formation, Nambo/Buya Formation, and Bobong Formation, shows that all three formations were deposited in a transitional environment that is more terrestrial with organic material dominated by higher plants. The Tomori Formation and Tokala Formation show that depositional environments are transitional environments that are more marine with organic material dominated by algae or bacteria. Oil is divided into three families based on biomarker analysis and HCA multivariate statistics i.e. Family 1 is dominated by a mixture of organic material of higher plant origin and algae, Family 2 by algae or plankton material with the presence of oleanane, and Family 3 by algae or plankton material without the presence of oleanane. Correlation analysis between source rocks and oils, shows that Family 1 correlates with the Matindok Formation (Middle Miocene), Family 2 correlates with the Tomori Formation (Early Miocene), and Family 3 correlates with the Tokala Formation (Late Triassic-Early Jurassic). Family 3 is also correlated with oil in the Seram Basin and Buton Basin, therefore a Mesozoic petroleum system in the Banggai Basin is confirmed. The natural and origin of gas in the Banggai Basin are divided into two types: thermogenic gas and biogenic gas. Biogenic gas correlates with Celebes Molasse; thermogenic gas present in the Eastern Arm of Sulawesi Island correlates with Matindok or Tomori Formation; and thermogenic gas in Mangole Island correlates with Nambo/Buya or Bobong Formation.