Korelasi Geokimia Antara Minyakbumi dengan Batuan Induk Melalui Karakter Biomarker di Cekungan Sumatera Selatan (2011)



Jambi Sub-basin was part of tertiary sedimentary basin in South Sumatera, as one of the Oil & Gas Field. Reservoir rock in this area was sandstone of Talangakar Formation and sandstone of Air Benakat Formation and also basement as the new objective for exploration. This research used data source rock samples and oil samples, from 15 wells from 3 different fields. The data from source rock samples were screening analyses, pyrolysis GC (Gas Chromatogram), extract data (Gas Chromatogram-Mass Spectogram), and extract data (Gas Chromatogram-Mass Spectogram) and data from oil samples were bulk properties, liquid chromatetography, oil-gas chromatography (GC), Gas Chromatogram-Mass Spectogram (GC-MS) and carbon isotopes Source rock sample from Sahara-2 had oil window at Upper Talangakar Formation (7550ft) with 0.73 of Ro, resulting kerogen type II dan gas window at Lower Talangakar Formation (9160ft) with 1.13 of Ro, resulting kerogen type III. According to analyses of GC and GC-MS data, the depositional environment in the research area was transitional in more oxic condition. The precursors of organic material in the research area were terrestrial plant and marine alga, because it has moderate ratio of pristane/phytane and pristane/nC17. Based on oil-to-oil and oil-to-source correlation by correlating chromatograms, oils and source rock in the research area has the same characteristics, those were depositional environment (transitional) and precursor (terrestrial). Assuming that basin developing system that developed in Sahara deep was same in the Mohave deep, Lower Talangakar Formation oils from Namib, Mohave, Kalahari, and Gobi field correlated with Upper Talangakar source Rock from Sahara Deep.

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Author : Reddy S, Hadi N, Wahju K, Teguh F, Beiruny S