Hostname: page-component-848d4c4894-2pzkn Total loading time: 0 Render date: 2024-06-02T03:13:52.472Z Has data issue: false hasContentIssue false
  • English
  • Français

Geochemical characteristics and resource potential analysis of Chang 7 organic-rich black shale in the Ordos Basin

Published online by Cambridge University Press:  19 December 2018

JIANGMIN DU ,
YANDE ZHAO ,
QINGCHUN WANG ,
YANQIU YU ,
HUI XIAO ,
XIANKUI XIE ,
YUGUO DU  and
ZIMIAO SU
JIANGMIN DU*
Affiliation:
College of Resources, Hebei GEO University, Shijiazhuang 050031, China
YANDE ZHAO
Affiliation:
BaiLie School of Petroleum Engineering, Lanzhou City University, Lanzhou 730070, China Exploration & Development Research Institute of PetroChina Changqing Oilfield Company, Xi’an 710018, China National Engineering Laboratory for Exploration and Development of Low-Permeability Oil & Gas Fields, CNPC, Xi’an, Shanxi 710018, China
QINGCHUN WANG
Affiliation:
College of Resources, Hebei GEO University, Shijiazhuang 050031, China
YANQIU YU
Affiliation:
College of Resources, Hebei GEO University, Shijiazhuang 050031, China
HUI XIAO
Affiliation:
Exploration & Development Research Institute of PetroChina Changqing Oilfield Company, Xi’an 710018, China National Engineering Laboratory for Exploration and Development of Low-Permeability Oil & Gas Fields, CNPC, Xi’an, Shanxi 710018, China
XIANKUI XIE
Affiliation:
Exploration & Development Research Institute of PetroChina Changqing Oilfield Company, Xi’an 710018, China National Engineering Laboratory for Exploration and Development of Low-Permeability Oil & Gas Fields, CNPC, Xi’an, Shanxi 710018, China
YUGUO DU
Affiliation:
Exploration & Development Research Institute of PetroChina Changqing Oilfield Company, Xi’an 710018, China National Engineering Laboratory for Exploration and Development of Low-Permeability Oil & Gas Fields, CNPC, Xi’an, Shanxi 710018, China
ZIMIAO SU
Affiliation:
College of Resources, Hebei GEO University, Shijiazhuang 050031, China
*
†Author for correspondence: Jiangmindu@sohu.com
Get access Rights & Permissions [Opens in a new window]

Abstract

The Ordos Basin is the largest and most important intracontinental sedimentary depression in China, and a significant amount of crude oil resources has developed within this Mesozoic formation. High-grade organic-rich shale is prevalent in the large-scale areas of the Chang 7 sedimentary stage and provides essential hydrocarbon resources for abundant oil enrichment in the Mesozoic. This research investigated the geochemical characteristics of Chang 7 shale using core samples and well logs and via laboratory tests. In addition, the microscopic components of the shale organic matter (OM), biological marker compounds, carbon isotopes, enrichment grade of trace elements, and elemental ratio were analysed systematically. Moreover, the aspects related to the shale OM source, sedimentary environment and resource potential were evaluated. Our results revealed that spherical alginate and calcium spherical alginate were predominant in the micropetrological components of the shale. Many biomarkers, including n-alkanes, steranes and terpanes, were detected in the gas chromatography – mass spectrometry spectra. An analysis of n-alkanes, regular sterane shapes (C21−/C22− and C26+C27/C28+C29), odd–even predominance index (OEP) and carbon preference index (CPI) values and carbon isotope distributions showed that OM was produced from aquatic organisms. The indicators of trace elements, such as Sr/Ba and V/V+Ni, combined with the biomarker compound in Pr/Ph and the gammacerane index showed the presence of a semi-deep – deep lake environment containing fresh–brackish water. In addition, the hydrocarbon conversion rate index and shale rock pyrolysis parameters revealed that Chang 7 has a high hydrocarbon generation ability and hydrocarbon expulsion efficiency.

Keywords

resource potentialgeochemical characteristicsshaleTriassic Chang 7Ordos Basin
Type
Original Article
Information
Geological Magazine , Volume 156 , Issue 7 , July 2019 , pp. 1131 - 1140
Copyright
Copyright © Cambridge University Press 2018 

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

Cheng, K., Wang, T. G. & Zhong, N. N. 1995. Geochemical Characteristics of Sourcerocks. Beijing: Higher Education Press, 17–40.Google Scholar
Fu, J. H., Yu, J. & Xu, L. M. 2015. New progress in exploration and development of tight oil in Ordos Basin and main controlling factors of large-scale enrichment and exploitable capacity. Petroleum Exploration and Development 42, 9–19.Google Scholar
Gao, G., Liu, X. Y., Wang, Y. H. et al. 2013. Characteristics and resource potential of the oil shale of Chang 7 Layer in Longdong Area, Ordos Basin. Earth Science Frontiers 20, 140–6.Google Scholar
Guo, Q. L., Chen, N. S., Song, H. Q. et al. 2013. Accumulation models and numerical models of tight oil: a case study from Yanchang Formation in Ordos Basin. Lithologic Reservoirs 25, 4–10, 20.Google Scholar
Liu, Z. J., Meng, Q. T. & Liu, R. 2009. Geochemical characteristics of oil of Eocene Jijuntun Formation and its geological significance, Fushun basin. Acta Petrologica Sinica 25, 2341–50.Google Scholar
Liu, C. L., Qin, H. & Che, P. 2005. Elemental geochemistry and sedimentary environments of source rocks of the Buxin Formation of Eocene in Sanshui Basin, Guangdong Province. Journal of Palaeogeography 7, 125–36.Google Scholar
Liu, J. H., Wu, Z. X. & Yu, S. 2005. Paleocence trace element geochemistry and itsgeological significance in Lishui sag. China Offshore Oil and Gas 17, 8–11.Google Scholar
Liu, X. Y., Zhao, Y. D. & Wang, F. 2015. Composition characteristics and significance of aromatic compounds in crude oils from Triassic and Jurassic reservoir in Southwestern Ordos Basin. Journal of Lanzhou University (Natural Science), 51 (1).Google Scholar
Meng, J. H., Liu, L. F. & Zhang, M. 2011.Indicative function of aromatic hydrocarbon in crude oil on depositional environment. Journal of China University of Mining &Technology 40, 901–6.Google Scholar
Meng, Q. X., Zhang, S. L. & Cui, M. Z. 1998.Distribution features of aromatics in lacustrine low-mature crude oils from different environments. Acta Sedimentologica Sinica 17, 112–20.Google Scholar
Miao, J. Y., Zhou, L. F. & Deng, K. 2004. Organic matters from Middle Permian source rocks of northern Xinjiang and their relationships with sedimentary environments. Geochimica 33, 424–30.Google Scholar
Tenger Liu, W.H., Xu, Y. C. & Chen, J. F. 2005. Correlative study on parameters of inorganic geochemistry and hydrocarbon source rocks formative environment. Advances in Earth Sciences 20, 103–200.Google Scholar
Yang, H., Niu, X. & Xu, L. 2016. Exploration potential of shale oil in Chang7 Member, Upper Triassic Yanchang Formation, Ordos Basin, NW China. Petroleum Exploration and Development 43, 511–20.CrossRefGoogle Scholar
Yang, H. & Zhang, W. Z. 2005. Leading effect of the Seventh Member high-quality source rock of Yanchang Formation in Ordos Basin during the enrichment of low-penetrating oil-gas accumulation: geology and geochemistry. Geochimica 34, 147–54.Google Scholar
Yang, H. & Zhang, W. Z. 2006. Leading effect of the Seventh Member high-quality source rock of Yanchang Formation in Ordos Basin during the enrichment of low-penetrating oil-gas accumulation: geology and geochemistry. Petroleum Exploration and Development 33, 289–93.Google Scholar
Zhang, W. Z., Yang, H. & Xie, L. Q. 2010. Lake-bottom hydrothermal activities and their influences on the high-quality source rock development: a case from Chang 7 source rocks in Ordos Basin. Petroleum Exploration and Development 37, 424–9.Google Scholar
Zhang, W. Z., Yang, H. & Xie, L. Q. 2011. Discovery of micro- and nannofossils in high grade hydrocarbon source rocks of the Triassic Yanchang Formation Chang 7 Member in Ordos Basin and its scientific significance. Acta Palaeontologica Sinica 50, 109–17.Google Scholar
Zhang, W. Z., Yang, H. & Yang, Y. H. 2008 a. Assessment of geological characteristics of lacustrine shale oil reservoir in Chang 7 Member of Yanchang Formation, Ordos Basin. Geochimica 44, 505–15.Google Scholar
Zhang, W. Z., Yang, H. & Yang, Y. H. 2008 b. Petrology and element geochemistry and development environment of Yanchang Formation Chang-7 high quality source rocks in Ordos Basin. Geochimica 37, 59– 64.Google Scholar
Zhao, Y. D., Liu, X. Y. & Zhang, X. F. 2011. Oil sources analysis of the Jurassic crude oil in the Southern Tianhuan Depression, Ordos Basin. Geoscience 25, 85–93.Google Scholar
Zhao, Y. D., Luo, A. X. & Sun, B. N. 2012. Hydrocarbon source evaluation and oil source contrast of the Triassic system in southwest margin, Ordos basin. Journal of Lanzhou University (Natural Science) 48, 1–6.Google Scholar
Zhao, Y. D., Yao, J. L. & Sun, B. N. 2014. Evidence of oil sources and migration inTriassic-Jurassic reservoirs in the South Tianhuan Depression of the Ordos Basin, China based on analysis of biomarkers and nitrogen-bearing compounds. Acta Geologica Sinica 88, 1801–14.Google Scholar