Genesis Analysis of High Gamma Ray (GR) Sandstone Reservoir: Taking Toutunhe Formation of Junggar Basin, Northwest China, as an Example

Abstract:

On the basis of GR log analysis alone, the high GR sandstone reservoirs would probably have been regarded as mudstone and interpreted to be non-reservoir, which has greatly affected the exploration and exploitation of oil and gas reservoir to some extent. Therefore, the principles and standards to distinguish high GR sandstone reservoir from conventional sandstone reservoir, genesis of high GR sandstone reservoir have been systematically studied. Studies show that sandstone reservoir with apparent shale content calculated by GR log value greater than 50%, can be regarded as high GR sandstone reservoir. In the study area, the specific criterion of GR log value for high GR sandstone reservoir is 110API. The high GR characteristic of sandstone reservoir is mainly and directly caused by an abnormally high uranium enrichment, but not the tuff, feldspar or clay mineral. The study area has favorable conditions of abundant uranium source, favorable paleoclimate, and favorable lithology and lithofacies combination for uranium enrichment. In the process of oxygen bearing formation water migrating and leaching uranium bearing tuff, the U⁺⁴ can be oxidized to U⁺⁶, and uranium element transports in the form of UO₂⁺². In permeable sandstone reservoir saturated with uranium bearing formation water, the U⁺⁶ can be deoxidized into U⁺⁴ by oil and gas migrating through faults and stratigraphic unconformities, and accumulates in the form of UO₂ in sandstones.

• Periodical: Applied Mechanics and Materials (Volume 394)
• Pages: 585-590
• DOI: https://doi.org/10.4028/www.scientific.net/AMM.394.585
• Online since: September 2013
• Authors: Liang Wang, Zhi Qiang Mao, Zhong Chun Sun, Xing Ping Luo, Yong Song
• Keywords: High Gamma Ray Sandstone, Reservoir, Reservoir Recognition, Uranium

References

[1] X.L. Zhang, Q. Feng, P. Sun and W. Li: Characteristics of high gamma ray reservoir of Yanchang formation in Ordos basin, Chinese Journal of Geophysics, vol. 53 (2010), pp.205-213.

DOI: 10.1002/cjg2.1482

[2] R.P. Sorenson: A dynamic model for the permian panhandle and Hougoton fields, western Anadarko basin, AAPG Bulletin, vol. 89 (2005), pp.921-938.

DOI: 10.1306/03010504045

[3] M.L. Passaretti, E.V. Eslinger and G.D. Hinterlong: High gamma ray zone from a core within a Permian dolostone sequenc, SPE 15333. (1986).

[4] G.R. Li, Q.Y. Guo, Y.J. Shi and C.H. Li: Identification of high gamma ray reservoir in Ordos Basin, Well Logging Technology, vol. 30 (2006), pp.511-515.

[5] T. Zhang, C.Y. Lin, X.G. Zhang, J.F. Yu, X.R. Lu and X.X. Zhang: Genesis analysis of high GR reservoir and its well-log based recongnition method, OGP, vol. 47 (2012), pp.491-495.

[6] J.L. Zhao, C.Q. Tan, C.Y. Liu and Q.C. Li: Abnormity features of obvious natural gamma in Ordos Basin, Journal of Earth Sciences and Environmen, vol. 28 (2006), pp.83-86.

[7] P. Sun, X.L. Zhang, L. Guo and Y.B. Shen: Genesis of the sandstone with higher radioactivity and the qualitative evaluation of its reservoir property: taking Chang 6 oil-bearing strata in Zhidan Oilfield Ordos Basin as an example, Journal of Xi'an Shiyou University (Natural Science Edition), vol. 25(2010).

[8] C.J. Xue, G.X. Chi and W. Xue: Effects of hydrocarbon generation on fluid flow in the Ordos Basin and its relationship to uranium mineralization, Geoscience Frontiers, vol. 2 (2011), pp.439-447.

DOI: 10.1016/j.gsf.2011.05.007

[9] C.J. Xue, G.X. Chi and W. Xue: Interaction of two fluid systems in the formation of sandstone-hosted uranium deposits in the Ordos Basin: Geochemical evidence and hydrodynamic modeling, Journal of Geochemical Exploration, vol. 106 (2010).

DOI: 10.1016/j.gexplo.2009.11.006

[10] H. Yang, W.Z. Zhang and K. Wu: Uranium enrichment in lacustrine oil source rocks of the Chang 7 member of the Yanchang Formation, Erdos Basin, China, Journal of Asian Earth Sciences, vol. 39 (2010), pp.285-293.

DOI: 10.1016/j.jseaes.2010.03.013

[11] Z.F. Yu, R.H. Cheng, X.Q. Zhao, F.X. Sun, Z.J. Xu and Y.J. Shen: Genesis and identification of high gamma sandstone in the first member of of Nantun formation of Wunan depression in Hailar Basin, Journal of China University of Petroleum, vol. 36 (2012).

[12] Mohamed Chaker Raddadi, Annie Arnaud Vanneau, Gérard Poupeau, Elisabeth Carrio-Schaffhauser, Hubert Arnaud and Alice Rivera: Interpretation of gamma-ray logs: The distribution of uranium in carbonate platform, C.R. Geoscience, vol. 337 (2005).

DOI: 10.1016/j.crte.2005.08.009

[13] X. Xu, C. Cheng, T.F. Ding, X.Y. Liu and H.Q. Li: Discovery of lisa basalt northwestern edge of Junggar Basin and it's geological significance, Xinjiang Geology, vol. 26 (2008), pp.9-16.

[14] D.R. Han, F.Z. Bai and S.X. Liu: Regional prognosis criteria for the sandstone type uranium deposits in interlayer oxidation zone and their application in the east of Junggar basin, Xinjiang, Uranium Geology, vol. 11 (1995), pp.129-138.

[15] J. Wang and L.T. Du: Gas reduction: an important factor in the formation of Uranium deposits, Uranium Geology, vol. 11 (1995), pp.19-24.

[16] H.B. Cheng, G.Z. Xu, M.L. Yang, J.P. Wang, W.H. Li and J.P. Quan: Direct evidences for reduction of pitchblende by pitch in the sawapuqi uranium deposit, Xinjiang, Bulletin of Mineralogy Petrology and Geochemistry, vol. 26 ( 2007), pp.246-248.

[17] S.X. Ling and G. Wang: Discovery of interlayer oxidation zone sandstone-type uranium mineralization in Lower Tertiary and its significance, Dingshan area, Junggar basin, Xinjiang, Uranium Geology, vol. 19 (2003), pp.264-270.

DOI: 10.1016/j.oregeorev.2021.104557