1887
Volume 30, Issue 1
  • ISSN: 1354-0793
  • E-ISSN:

Abstract

In this study we used the concept of inverse rock physics modelling to analyse reservoir properties of the Kanywataba Exploration Area, with a focus on their lateral distribution away from the Kanywataba well. The procedure employed rock physics models calibrated for the basin constrained by seismic inversion data, where non-uniqueness and data error propagation issues were also taken into account. Both seismic and well log datasets were used in the data calibration. The procedures enabled us to obtain the most likely estimate mean, weighted mean and posterior mean of the reservoir properties. We obtained a good match between measured and modelled porosity values. Any misfit between the observed and predicted lithology was mainly attributed to uncertainties in defining the correct mineral properties. The integrated approach revealed that high porosities correlate with low clay volumes and, furthermore, indicated two distinct reservoir units in the basin, which were interpreted as the Oluka and Kakara Formations. Fluid saturation data were less successfully predicted but this was most probably due to a result of lack of real saturation logs for use in the calibration of the rock physics model; instead, predicted saturation logs based on Archie's law were used in the calibration process. This analysis is first of its kind in this basin and therefore exhibits a high level of novelty in the determination of reservoir properties in this area.

Loading

Article metrics loading...

/content/journals/10.1144/petgeo2023-031
2024-02-12
2024-04-27
Loading full text...

Full text loading...

References

  1. Abeinomugisha, D.2010. Development of a petroleum system in a young rift basin prior to continental breakup: The Albertine Graben of the East African Rift System. Presented at theAAPG International Convention and Exhibition, 12–15 September, 2010, Calgary, Alberta, Canada.
    [Google Scholar]
  2. Abeinomugisha, D. and Njabire, N.2012. Transfer zones and hydrocarbon accumulation in the Albertine Graben of the East African Rift System. Search and Discovery Article #10401, AAPG Annual Convention and Exhibition, 22–25 April 2012, Long Beach, California, USA.
    [Google Scholar]
  3. Bauer, F.U., Glasmacher, U.A., Ring, U., Schumann, A. and Nagudi, B. 2010. Thermal and exhumation history of the central Rwenzori Mountains, Western Rift of the East African Rift system, Uganda. International Journal of Earth Sciences, 99, 1575–1597, https://doi.org/10.1007/s00531-010-0549-7
    [Google Scholar]
  4. Bredesen, K., Jensen, E.H., Johansen, T.A. and Avseth, P. 2015a. Quantitative seismic interpretation using inverse rock physics modelling. Petroleum Geoscience, 21, 271–284, https://doi.org/10.1144/petgeo2015-006
    [Google Scholar]
  5. Bredesen, K., Jensen, E.H., Johansen, T.A. and Avseth, P. 2015b. Seismic reservoir and source-rock analysis using inverse rock-physics modeling: a Norwegian Sea demonstration. The Leading Edge, 34, 1350–1355, https://doi.org/10.1190/tle34111350.1
    [Google Scholar]
  6. Dvorkin, J.P. and Nur, A.M.1995. Elasticity of high-porosity sandstones: Theory for two North Sea datasets. SEG Technical Program Expanded Abstracts, 1995, 890–893, https://doi.org/10.1190/1.1887538
    [Google Scholar]
  7. Dvorkin, J. and Nur, A.1996. Elasticity of high-porosity sandstones: Theory for two North Sea data sets. Geophysics, 61, 1363–1370, https://doi.org/10.1190/1.1444059
    [Google Scholar]
  8. Gassmann, F.1951. Elastic waves through a packing of spheres. Geophysics, 16, 673–685, https://doi.org/10.1190/1.1437718
    [Google Scholar]
  9. Hill, R. 1963. Elastic properties of reinforced solids: Some theoretical principles. Journal of the Mechanics and Physics of Solids, 11, 357–372, https://doi.org/10.1016/0022-5096(63)90036-X
    [Google Scholar]
  10. Jensen, E.2011. Methods for Improved Prediction of Elastic, Electrical and Reservoir Properties. Doctoral thesis, University of Bergen, Bergen, Norway.
    [Google Scholar]
  11. Jensen, E.H., Johansen, T.A., Avseth, P. and Bredesen, K. 2016. Quantitative interpretation using inverse rock-physics modeling on AVO data. Leading Edge, 35, 677–683, https://doi.org/10.1190/tle35080677.1
    [Google Scholar]
  12. Jensen, E.H., Drottning, Å. and Littman, M.2019. Extending the AVO toolbox with rock physics driven inversion for seismic interpretation with little or no well control: Example from the Norwegian Sea. SEG Technical Program Expanded Abstracts, 2019, 704–708, https://doi.org/10.1190/segam2019-3216194.1
    [Google Scholar]
  13. Johansen, T.A., Jensen, E.H., Mavko, G. and Dvorkin, J. 2013. Inverse rock physics modeling for reservoir quality prediction. Geophysics, 78, M1–M18, https://doi.org/10.1190/geo2012-0215.1
    [Google Scholar]
  14. Khadem, B., Saberi, M. R., Eslahati, M. and Arbab, B. 2020. Integration of rock physics and seismic inversion for rock typing and flow unit analysis: a case study. Geophysical Prospecting, 68, 1613–1632, https://doi.org/10.1111/1365-2478.12952
    [Google Scholar]
  15. Lukaye, J., Worsley, D. et al.2013. Stratigraphy of the Albertine Graben. Directorate of Petroleum, Ministry of Energy and Mineral development, Uganda.
  16. Lukaye, J., Worsley, D. et al.2016. Developing a coherent stratigraphic scheme of the Albertine Graben–East, Africa. Journal of Earth Science and Engineering, 6, 264–294, https://doi.org/10.17265/2159-581x/2016.05.004
    [Google Scholar]
  17. Moyano, B., Jensen, E.H. and Johansen, T.A. 2011. Improved quantitative calibration of rock physics models. Petroleum Geoscience, 17, 345–354, https://doi.org/10.1144/1354-079311-028
    [Google Scholar]
  18. Moyano, B., Jensen, E.H. and Johansen, T.A. 2015. Spatial constrained inverse rock physics modelling. Geophysical Prospecting, 63, 183–191, https://doi.org/10.1111/1365-2478.12178
    [Google Scholar]
  19. Mukerji, T., Jørstad, A., Mavko, G. and Granli, J.R.1998. Applying statistical rock physics and seismic inversions to map lithofacies and pore fluid probabilities in a North Sea reservoir. SEG Technical Program Expanded Abstracts, 1998, 894–897, https://doi.org/10.1190/1.1820633
    [Google Scholar]
  20. Nakajigo, J., Kiberu, J.M., Johansen, T.A., Jensen, E.H. and Tiberindwa, J.V. 2023. Rock physics analysis of reservoir units of the Semliki basin, Albertine graben: A case study. Journal of African Earth Sciences, 200, 104876, https://doi.org/10.1016/j.jafrearsci.2023.104876
    [Google Scholar]
  21. Ødegaard, E. and Avseth, P. 2004. Well log and seismic data analysis using rock physics templates. First Break, 22, 37–43, https://doi.org/10.3997/1365-2397.2004017
    [Google Scholar]
  22. Purcell, P.G. 2018. Re-imagining and re-imaging the development of the East African Rift. Petroleum Geoscience, 24, 21–40, https://doi.org/10.1144/petgeo2017-036
    [Google Scholar]
  23. Roller, S., Hornung, J., Hinderer, M. and Ssemmanda, I. 2010. Middle Miocene to Pleistocene sedimentary record of rift evolution in the southern Albert Rift (Uganda). International Journal of Earth Sciences, 99, 1643–1661, https://doi.org/10.1007/s00531-010-0560-z
    [Google Scholar]
  24. Russell, B. and Hampson, D. 2006. The old and the new in seismic inversion. CSEG Recorder, 31, 5–11.
    [Google Scholar]
  25. Simm, R. and Bacon, M.2014. Seismic Amplitude: an Interpreter's Handbook. Cambridge University Press, Cambridge, UK, https://doi.org/10.1017/CBO9780511984501
    [Google Scholar]
  26. Walpole, L.J. 1966a. On bounds for the overall elastic moduli of inhomogeneous systems – I. Journal of the Mechanics and Physics of Solids, 14, 151–162, https://doi.org/10.1016/0022-5096(66)90035-4
    [Google Scholar]
  27. Walpole, L.J. 1966b. On bound for the overall elastic moduli of inhomogeneous system – II. Journal of the Mechanic and Physics of Solid, 14, 289–301, https://doi.org/10.1016/0022-5096(66)90025-1
    [Google Scholar]
  28. Wood, A.B.1955. A textbook of sound: being an account of the physics of vibrations with special reference to recent theoretical and technical developments. G. Bell, London, https://doi.org/10.1063/1.3059819
    [Google Scholar]
  29. Yang, X. Yu, Y., Dong, Y. and Sun, Y.2012. Final Geological Report of Kanywataba-l Well in Kanywataba Exploration Area, Uganda. Department of Geology and Petroleum Studies of Makerere University, Kampala.
    [Google Scholar]
  30. Zhang, R. and Castagna, J. 2011. Seismic sparse-layer reflectivity inversion using basis pursuit decomposition. Geophysics, 76, R147–R158, https://doi.org/10.1190/geo2011-0103.1
    [Google Scholar]
http://instance.metastore.ingenta.com/content/journals/10.1144/petgeo2023-031
Loading
/content/journals/10.1144/petgeo2023-031
Loading

Data & Media loading...

  • Article Type: Research Article

Most Cited This Month Most Cited RSS feed

This is a required field
Please enter a valid email address
Approval was a Success
Invalid data
An Error Occurred
Approval was partially successful, following selected items could not be processed due to error