The Radioactive Sands & Low-Resistivity Low-Contrast Pays Reservoir in Deta Field, Niger Termit Basin

  • Abstract
  • Keywords
  • References
  • PDF
  • Abstract

    Radioactive and low-resistivity pay sands are often petrophysically underestimated under conventional exploration approaches. Deta Field is a good example of hydrocarbon producing field with low resistivity contrast and radioactive sands. Deta field located in the South-West flank of Dinga Trough, Termit Basin. Hydrocarbon had been discovered and produced from Alter Sokor formation, E0-E5 sand zones. Radioactive sands found in Deta field reservoir formations are due to clay minerals in sandstone composition. Types of clay minerals in radioactive sands are studied from E0 and E1 formations after the crossplot analysis using Spectral Gamma Ray (SGR) log, photoelectric log, and density-neutron log crossplot. High percentage of illite are found as types of clay minerals in radioactive sand. The low resistivity pays identified in the main hydrocarbon producing reservoir sand zones are due to the dispersed clay minerals. The oil-producing reservoir sandstone recorded with relatively low resistivity curve of 15 - 20 ohm∙m only. The difference of resistivity curve between reservoir intervals and adjacent shale formation is less than 7 ohm∙m. This study aims to understand the clay content in radioactive sands and relate to low resistivity pays reservoir. This research finds that both reservoir problems of radioactive sands & low resistivity pays are indirectly related.



  • Keywords

    radioactive high GR sand; low resistivity low contrast (LRLC) pays; highly conductive; petrophysical underestimation; clay minerals; geological facies

  • References

      [1] O. Chudi and R. Simon, “Radioactive sand is sediments sourced from nearby granitic highlands and have not undergone sufficient transportation and weathering.,” no. Obuaya 1989, pp. 1–8, 2012.

      [2] G. M. Hamada, M. S. Almalik, and S. Arabia, “Log Evaluation of Low - Resistivity Sandstone Reservoirs,” SPE Annu. Tech. Conf. Exhib., no. SPE 70040, 2001.

      [3] M. Zhiqiang, K. Lichurr, X. Chengwen, and O. Jians, “Identification and Evaluation of Low Resistivity Pay Zones” vol. 4, no. 1, 2007.

      [4] M. Claverie, D. F. Allen, N. Heaton, and G. Bordakov, “A New Look at Low-Resistivity and Low-Contrast ( LRLC ) Pay in Clastic Reservoirs,” SPE Annu. Tech. Conf., no. SPE 134402, 2010.

      [5] M. Zhiqiang, Z. Cancan, and O. Jian, “Identificatio and Evaluation of Low Resistivity pay Zones by Well Logs and the Petrophysical Reserach in China,” vol. 8, no. l, 2007.

      [6] G. M. Hamada and M. N. J. Al-Awad, “Petrophysical Evaluation of Low Resistivity Sandstone Reservoirs,” JCPT, vol. 39, no. 7, pp. 7–14, 2000.

      [7] B. Harold A and J. L. Martin, “LOG INTERPRETATION PROBLEM in LOW RESISTIVITY SANDS,” J. Pet. Technol., 1955.

      [8] W. Chu, J. Steckhan, and E. Omv, “A Practical Approach to Determine Low-Resistivity Pay in Clastic Reservoirs,” SPE Annu. Tech. Conf., vol. SPE 147360, no. 2006, 2011




Article ID: 18894
DOI: 10.14419/ijet.v7i3.7.18894

Copyright © 2012-2015 Science Publishing Corporation Inc. All rights reserved.