Geochemistry of Natural Gas Seepages in Boto Area, Bancak, Semarang, Central Java
DOI:
https://doi.org/10.17014/ijog.4.2.61-70Keywords:
isotope, gas seepage, methane, Boto, BancakAbstract
Three seepage gas samples collected from Boto Area, Bancak, Semarang, Central Java, were studied to determine their chemical characteristics using GC and GC-IRMS methods. They are composed 53 - 85% of methane predominantly. However, gas seep Site 3 sample has the highest N2 compound and the lesser extent to the samples Site 2 and Site 1 respectively. The two hydrocarbon gas seeps (Site 1, 2, and Site 3 samples) that are characterized by δ13C methane of -35.61‰ and -27.97‰, and values of δD methane of -112‰ and -109‰ respectively, are each isotopically distinct from all others suggesting, at least, they are derived from different maturity level. The Site 3 gas sample is suggested to be more mature than the others.
References
Amijaya, D. H. dan Winardi, S., 2006. Geokimia Rembesan Air Formasi dan Gas Alam Di Desa Boto, Kecamatan Bancak, Kabupaten Semarang. Laporan Penelitian, Fakultas Teknik Universitas Gadjah Mada, Yogyakarta. 28 pp.
Berner, U. and Faber, E., 1996. Empirical carbon isotope/maturity relationships for gases from algae kerogens and terrigenous organic matter, based on dry, open-system pyrolysis. org. geochem. 24, p.947-955 DOI: 10.1016/S0146-6380(96)00090-3
BNPB, 2010. Topography map of Semarang District scale 1:250.000. https://geospasial.bnpb.go.id/wp-content/uploads/2010/09/indeks_peta/250K/ID-N09-250K.pdf
de Genevraye, P. and Samuel, L., 1972. Geology of The Kendeng Zone (Central & East Java), Proceedings of First Annual Convention Indonesian Petroleum Association, p.17-30
Hunt, J.M., 1996. Petroleum Geochemistry and Geology. 2nd Edition. W.H. Freeman and Company, New York. 743 pp. DOI: 10.1017/S0016756800007755
Jenden, P. D., Drazan, D. J., and Kaplan, I. R.,1993. Mixing of thermogenic natural gases in northern Appalachian Basin. The American Association of Petroleum Geologists Bulletin, 77, p.980-998.
Katz, B.J., 2001. Gas geochemistry – a key to understanding formation and alteration processes. Proceedings of 28th Annual Convention Indonesian Petroleum Association, p.789-802.
Laughrey, C. D. and Baldassare, F. J., 1998. Geochemistry and origin of some natural gases in the Plateau Province, central Appalachian Basin, Pennsylvania and Ohio. The American Association of Petroleum Geologists Bulletin, 82, p.317-335.
Pramono, W., 2008. Studi Geokimia Rembesan Minyak Bumi di Daerah Bantal, Kecamatan Bancak, Kabupaten Semarang, Propinsi Jawa Tengah. Bachelor Thesis at Geological Engineering Departement, Faculty of Engineering, Universitas Gadjah Mada, Yogyakarta. 90 pp.
Rice, D.D., 1993. Composition and origins of coalbed gas. In: Law, B.E., Rice, D.D. (Eds.), Hydrocarbons from Coal. American Association of Petroleum Geologists, Tulsa, Oklahoma, p.159-184.
Schoell, M., 1983. Genetic Characterization of Natural Gases. The American Association of Petroleum Geologist, Bulletin, 67, No 12, p.2225-2238.
Smith, H., Hall, R., Hamilton, J.P., and Kinny, P., 2005. East Java: Cenozoic basins, volcanoes and ancient basement. Proceedings of 30th Indonesian Petroleum Association Annual Convention, Jakarta, p.251-266.
Sukardi and Budhitrisna, T., 1992. Peta Geologi Lembar Salatiga, Jawa. skala 1:100.000. Pusat Penelitian dan Pengembangan Geologi, Bandung.
Van Bemmelen, R. W., 1949. The Geology of Indonesia, vol. I A, General Geology of Indonesia and Adjacent Archipelagoes, Special Edition of The Bureau of Mines In Indonesia. Department of Transport, Energy and Mining, Batavia. 732 pp.
Wiloso, D.A. 2008. Studi Batuan Induk Hidrokarbon Di Cekungan Jawa Timur Bagian Barat. Abstract of Master Thesis at Geological Engineering Magister Study Program, Institut Teknologi Bandung, Jawa Barat.
Wiloso, D.A., Subroto, E.A., Hermanto, E., 2009. Confirmation of the Paleogene Source Rocks in the Northeast Java Basin, Indonesia, Based from Petroleum Geochemistry [Presentation Slide]. AAPG International Conference and Exhibition, South Africa. 33 pp.
