Abstract
The Yong’an-Meitai area is the focus of the present exploration in the Fushan Depression, Beibuwan Basin, South China Sea. All oils from this area are geochemically characterized by higher Pr/Ph ratio, higher proportion of heavy molecular weight hydrocarbons, and higher proportion of C29 regular steranes, which indicate that the organic matter of source rocks might have been deposited in an oxidizing palaeoenvironment and be dominated by higher plant organic matter input. The oil from E3 w 2 (the second member of Weizhou Fm. of the Oligocene) has a much higher density, relatively higher Pr/nC17 and Ph/nC18 ratios, and a “UCM—unresolved complex mixture” on gas chromatograms, which indicate that it has been slightly biodegraded. CPI and other terpane and sterane isomer ratios suggest they are all mature oils. The timing of oil charging in E3 w 2 and E2 l 1 (the first member of the Liushagang Fm. of the Eocene) determined by the homogenization temperatures of fluid inclusions and thermal evolution history are from 9-3 Ma and 8-3 Ma, respectively. Thus, the interpretation of E3 w 2 as a secondary reservoir is unlikely. The timing of oil charging is later than that of hydrocarbon generating and expulsion of Liushagang Fm. source rocks and trap formation, which is favorable for oil accumulation in this area. All molecular parameters that are used for tracing oil filling direction decrease with shallower burial depth, which suggests vertical oil migration. The widely occurring faults that penetrate through the source rocks of the Liushagang Fm. may serve as a fine oil charging conduit.
Article PDF
Similar content being viewed by others
Explore related subjects
Discover the latest articles, news and stories from top researchers in related subjects.Avoid common mistakes on your manuscript.
References
Alexander R., Kagi R. I., Rowland S. J.,et al. (1985) The effects of thermal maturity on distribution of dimethylnaphthalenes and trimethylnaphthalenes in some ancient sediments and petroleums.Geochemica et Comochimica Acta, 49, 385–395
Chakhmakhchev A., Suzuki M., Waseda A.,et al. (1997) Distribution of alkylated dibenzothiophenes in petroleum as a tool for maturity assessments.Organic Geochemistry, 26(7–8), 483–490
Connan J., Bouroullec J., Dessort D.,et al. (1986) The microbial input in carbonate-anhydrite facies of Sabkha palaeoenvironment from Guatemala: A molecular approach. Advances in Organic Geochemistry (edited by Leythhaeuser D. and Rullkötter J.).Organic Geochemistry, (10), 29–50
England W., Mackenzie A. S., Mann D. M.,et al. (1987) The movement and entrapment of petroleum fluids in the subsurface.Journal of Geological Society, 144, 327–347
Gong Z. S. (1997)The Major Oil and Gas Fields of China Offshore. Beijing: Petroleum Industry Press. 199–222 (in Chinese)
Hughes W. B. (1984) Use of thiophenic organosulfur compounds in characterizing crude oils derived from carbonate versus siliclastic sources. In:Petroleum Geochemistry and Source Rock Potential of Carbonate Rocks (edited by Palacas J. B.). AAPG Studies in Geology, 18, 181–196, AAPG Press, Oklahoma
Larter S. R. and Aplin A. C. (1995) Geochemistry of reservoirs: An introduction. In:The Geochemistry of Reservoirs (edited by Cubitt J. M. and England W. A.). London: The Geological Society Publishing House. 5–32
Li M., Fowler M. G., Obermajor M.,et al. (1999a) Geochemical characterization of Middle Devonian oils in NW Alberta, Canada: Possible source and maturity effect on pyrrolic nitrogen compounds.Organic Geochemistry, 30, 1039–1057
Li M., Larter S. R., Stoddart D.,et al. (1995) Fractionation of pyrrolic nitrogen compounds in petroleum during migration-related geochemical parameters. In:The Geochemistry of Reservoirs (edited by Cubitt J. M. and England W. A.). London: The Geological Society Publishing House. 103–123,
Li M., You H., Fowler M. G.,et al. (1998) Geochemical constraints on models for secondary petroleum migration along the Upper Devonian Rimbey-Meadowbrook reef trend in central Alberta, Canada.Organic Geochemistry, 29, 163–182
Li M. J., Wang T. G., Liu J.,et al. (2007a) Occurrence and origin of carbon dioxide in the Fushan Depression, Beibuwan Basin, South China Sea.Marie and Petroleum Geology, Dio: 10.1016/j.marpetgeo.2007.07.007.
Li M. J., Wang T. G., Liu J.,et al. (2007b) The discussion on hydrocarbon accumulation dating determined by homogenization temperature and burial history of fluld inclusion: An example from the Fushan Depression.Oil & Gas Geology, 2007, 28(2), 151–158
Li S. M., Zhang A. Y., Wang T. G.,et al. (1999b) Evolution of isolation schemes of nitrogenous compounds.Geochimica, 28(4), 397–404 (in Chinese)
Peters K. E., Walters C. C. and Moldowan J. M. (2005)The Biomarker Guide (2nd edition). New York: Cambridge University Press, 525–527
Qiu Z. J. and Gong Z. S. (1999)Oil Exploration in China (Vol. 4): Offshore. Beijing: Geological Publishing House and Petroleum Industry Press, 194 (in Chinese)
Radke M., Garrigues P. and Willsch H. (1990) Methylated dicyclic and tricyclic aromatic hydrocarbons in crude oils from the Handil Field, Indonesia.Organic Geochemistry, 15, 17–34
Radke M., Rullkotter J. and Vriend S. P. (1994) Distribution of naphthalenes in crude oils from the Java Sea: Source and maturation effects.Geochemica et Cosmochimica Acta, 52, 1255–1264
Stoddart D. P., Hall P. B., Larter S. R.,et al. (1995) The reservoir geochemistry of the Edifisk Field, Norwegian North Sea. In:The Geochemistry of Reservoirs (edited by Cubitt J. M. and England W. A.). London: The Geological Society Publishing House. 257–279
van Aarssen B. G. K., Bastow T. P., Alexander R.,et al. (1999) Distributions of methylated naphthalenes in crude oils: Indicators of maturity, biodegradation and mixing.Organic Geochemistry, 30, 1213–1227
Wang T. G., He F. Q., Li M. J.,et al. (2004a) Alkyl-dibenzothiophenes: Molecular tracers for filling pathway in oil reservoirs.Chinese Science Bulletin, 49(22), 2399–2404
Wang T. G., Li S. M. and Zhang S. C. (2004b) Oil migration in the Lunnan region, Tarim Basin, China based on the pyrrolic nitrogen compound distribution.Journal of Petroleum Science & Engineering, 41(1), 123–134
Zhang C. M., Li S. T., Yang J. M.,et al. (2004) Petroleum migration and mixing in the Pearl River Mouth Basin, South China Sea.Marine and Petroleum Geology, 21, 215–224
Author information
Authors and Affiliations
Additional information
Li Meijun was born in 1972 and received his PhD degree from the China University of Geosciences in 2003. He is now a lecturer in the China University of Petroleum (Beijing), with his interests in reservoir geochemistry, molecular and environmental geochemistry. E-mail: meijunli2008@yahoo.com
Rights and permissions
About this article
Cite this article
Meijun, L., Tieguan, W., Ju, L. et al. Characteristics of oil and gas accumulation in Yong’an-Meitai area of the Fushan Depression, Beibuwan Basin, South China Sea. Pet. Sci. 4, 23–33 (2007). https://doi.org/10.1007/BF03187452
Received:
Issue Date:
DOI: https://doi.org/10.1007/BF03187452