CHARACTERIZATION OF HYDROCARBON AND SOURCE ROCK IN BEREMBANG-KARANGMAKMUR DEEP JAMBI SUB BASIN

• Main Author: Al Mizani, Yosa
• Format: Theses
• Language: Indonesia
• Subjects: Geologi, hidrologi & meteorologi
• Online Access: https://digilib.itb.ac.id/gdl/view/73314
• Institution: Institut Teknologi Bandung

Berembang-Karangmakmur deep in Jambi Sub-Basin belongs to PT Pertamina EP. This area has not been intensively explored. After doing some drilling in the area, it seems that productivity decreased. This phenomenon can be seen from the success ratio in this area which is around 51%. This study intends to explore the geochemical aspect, in this case assesing the characteristics of liquid hydrocarbons and source rocks around the deep, beside to understand to source potential for Gumai Formation. Evaluation done during this study used twelve well data comprising source rocks, gases, and crude oils. Geochemical characteristics of the samples were based on some analyses, such as kerogen type, Rock-Eval pyrolysis, gas chromatography, biomarkers through GC-MS analysis, and carbon isotope. Some correlations, such as oil to oil, oil to source rock, and gas to source rock that have been applied in the study area, in fact, could give a better explanation with regard to the hydrocarbon existence in the area. Maturity modelling and assessment of the migration pathway may confirm the history of the hydrocarbon generation and migration in the area. Crude oils collected from Talang Akar and Gumai Formations could be differed based on their biomarkers content. Crude oils from Talang Akar Formation were generally deposited in the fluvio-deltaic environment whereas those of Gumai Formation might be deposited in a marine environment. Based on carbon isotope, gas generated in the Berembang-Karangmakmur deep may be classified as thermogenic gas with relatively high maturation. Source rocks of Talang Akar and Gumai Formations contain types II and III kerogens. The Gumai shale has been deposited in a marine environment that is rich of algae material. On the other hand, the Talang Akar shale might be deposited in a fluvio-deltaic environment. In term of maturity, the Talang Akar sediments seem to be relatively mature whereas those of Gumai appear to be just mature. The oil to source correlation between crude oils collected from Gumai Formation and the sediments of Gumai Fomation indicate that they have a good correlation. This phenomenon indicates that the Gumai Formation in the deeper position may have been mature that they could produce some crude oils that were trapped within this formation. The results of 2D basin modelling show that hydrocarbons produced by the local deep had charged the nearest local reservoir since the local reservoir since the local reservoir (north and south) are separeted by some sealing faults.