Inversion Geochemistry as a Method for Interpreting Source Rock Criteria of Oil Samples: A Case Study from the Bobonaro Area, Maliana Basin, Timor-Leste
DOI:
https://doi.org/10.25299/jgeet.2025.10.1.1.24362Keywords:
Bobonaro, Timor Leste, Source Rock, Crude Oil, Inversion GeochemistryAbstract
In general condition, crude oil samples are difficult to obtain. However, when the crude oil samples are obtained, researchers will be able to estimate the possibility of their source rock, as long as the samples are analyzed in sufficient detail. In this study, the samples used as case studies are the Pualaka and Suai Loro oil seepage samples from Bobonaro area, Maliana Basin, Timor Leste. The petroleum samples obtained happened to be in relatively fresh condition. The analysis carried out included analysis using GC and GC-MS with the objects of analysis being biomarkers, i.e. triterpane compounds with m/z 191 and steranes with m/z 217. The results obtained showed that the two seepage oils were suspected to belong to one oil family whose source rock was estimated to be deposited in a marginal marine area with a dominant algae supply and few higher plants with Pre-Tertiary geological age. The maturity of the two petroleum samples was relatively high, at the stage of peak oil generation. By knowing such characters, researchers will be able to predict sedimentary rocks in the basin area that are of the same type as petroleum characters using inversion geochemistry technique. The most possible source rock of the crude oils is the Babulu Formation.
Downloads
References
Andriany, R., Al Khamiss, A., Al-Fares, A., Akbar, H. and Al-Ali, S. (2012) ‘Geochemical inversion: A breakthrough to determine the Cretaceous petroleum system in Kuwait’, Proceedings of the 10th Middle East Geosciences Conference and Exhibition (GEO 2012), Manama, Bahrain.
Azevedo, D.D., Aquino Neto, F.A., Simoneit, B.R.T. and Pinto, A. (1992) ‘Novel series of tricyclic aromatic terpanes characterized in Tasmanian tasmanite’, Organic Geochemistry, 18(1), pp. 9–16. doi:10.1016/0146-6380(92)90138-N
Bissada, K.K., Elrod, L.W., Darne, L.M., Szymczyk, H.M. and Trostle, J.L. (1992) ‘Geochemical inversion: A modern approach to inferring source-rock identity from characteristics of accumulated oil and gas’, Proceedings of the Indonesian Petroleum Association Twenty-First Annual Convention, Vol. 1, pp. 165–199.
Charlton, T.R. and Gandara, D. (2014) ‘The petroleum potential of onshore Timor-Leste’, Proceedings of the Indonesian Petroleum Association Convention, Paper IPA14-G-017.
Crostella, A. and Powell, D. (1975) ‘Geology and hydrocarbon prospects of the Timor area’, Proceedings of the Indonesian Petroleum Association Convention, Vol. 1, pp. 149–163.
Gageonnet, R. (1958) Contribution à la connaissance de la géologie de la province portugaise de Timor. Estudos, Ensaios e Documentos No. 48. Lisboa: Junta de Investigações Científicas do Ultramar, pp. 1–138.
Gageonnet, R. and Lemoine, M. (1957) ‘Sur la stratigraphie de l’autochtone au Timor portugais’, Comptes Rendus Hebdomadaires des Séances de l’Académie des Sciences, 244, pp. 2168–2171.
Huang, W.Y. and Meinschein, W.G. (1979) ‘Sterols as ecological indicators’, Geochimica et Cosmochimica Acta, 43(5), pp. 739–745. doi:10.1016/0016-7037(79)90257-6
Instituto Petróleo e Geologia (IPG) (2020) Evaluation of petroleum system in the Maliana Basin, Timor-Leste. Unpublished report, pp. 1–70.
Jorge, L.M., Camacho, H. and Guevara, J. (2021) ‘Geochemical inversion applied to oil samples from Lower Cretaceous reservoirs, Southeast Abu Dhabi: Implications for hydrocarbon exploration’, paper presented at the Abu Dhabi International Petroleum Exhibition and Conference (ADIPEC), Abu Dhabi, UAE, November. SPE-207558-MS. doi:10.2118/207558-MS
Kaneko, Y., Shigenori, M., Ade, K., Tsutomu, O., Masahiro, I., Tatsuki, T., Akira, I. and Kazuaki, O. (2006) ‘On-going orogeny in the outer arc of the Timor–Tanimbar region, eastern Indonesia’, Gondwana Research.
Peters, K.E., Fraser, T.H., Amris, W., Rustanto, B. and Hermanto, E. (1999) ‘Geochemistry of crude oils from eastern Indonesia’, AAPG Bulletin, 83, pp. 1927–1942. doi:10.1306/E4FD4643-1732-11D7-8645000102C1865D
Syaifudin, M. (2016) ‘Organic geochemical characteristics of crude oils from the Orange Graben, South Sumatra Basin’, Journal of Geoscience, Engineering, Environment, and Technology, 1, pp. 27–34. doi:10.24273/jgeet.2016.11.3
Volkman, J.K. (1986) ‘A review of sterol markers for marine and terrigenous organic matter’, Organic Geochemistry, 9, pp. 84–99. doi:10.1016/0146-6380(86)90089-6
Downloads
Published
Issue
Section
License
Copyright (c) 2026 Journal of Geoscience, Engineering, Environment, and Technology
This work is licensed under a Creative Commons Attribution-ShareAlike 4.0 International License.
Copyright @2019. This is an open-access article distributed under the terms of the Creative Commons Attribution-ShareAlike 4.0 International License which permits unrestricted use, distribution, and reproduction in any medium. Copyrights of all materials published in JGEET are freely available without charge to users or / institution. Users are allowed to read, download, copy, distribute, search, or link to full-text articles in this journal without asking by giving appropriate credit, provide a link to the license, and indicate if changes were made. All of the remix, transform, or build upon the material must distribute the contributions under the same license as the original.
