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The Influence of Depositional and Maturation Factors on the Three-Dimensional Distribution of Coal Rank Indicators and Hydrocarbon Source Potential in the Gunnedah Basin, New South Wales

  • Lila W. Gurba
  • Colin R. Ward
Chapter

Abstract

Three-dimensional modelling of vitrinite reflectance has been used to enhance the understanding of lateral and vertical rank variations in the Permian coals of the Gunnedah Basin, New South Wales, Australia. The level of organic maturity of the coals has been investigated using both petrographic (vitrinite reflectance and fluorescence) and chemical methods (proximate and ultimate analyses, and electron microprobe data). The coal is of high-volatile bituminous rank, with a mean maximum vitrinite reflectance of between 0.56 and 1.1%. In addition to maturation-induced trends, a significant influence of depositional environment has been identified on vitrinite reflectance and other coal rank indicators in different parts of the sequence.

Lower than normal vitrinite reflectance is developed in several parts of the Permian sequence, where marine strata overlie the coal-bearing interval or where lower delta plain facies are present. The coals in these intervals have a perhydrous character, increased fluorescence intensity and contain framboidal pyrite, that combine to make them distinctive in petrographic studies. When plotted against depth all vitrinite reflectance values in these parts of the sequence are shifted to the lower side of the more “normal” depth/reflectance regression line. Such anomalies can be recognised at equivalent horizons over wide areas, suggesting basin-wide marine flooding events. If not allowed for in some sections rank, as expressed by vitrinite reflectance or volatile matter content, would appear to decrease instead of increase with depth.

Coals in other parts of the section have anomalously high vitrinite reflectance values, and contain hydrogen-poor material described elsewhere as ‘pseudovitrinite’. Data from such coals plot to the right of the regression line in vitrinite reflectance profiles.

Chemical and petrographic studies show that the different vitrinite types follow separate coalification tracks, and hence both high and low-value anomalies need to be taken into account when interpreting maturation patterns. The depositional controls and the rank trends both have implications to maturation studies, and to prospectivity mapping for coalbed methane and petroleum generation.

Keywords

Coal Seam Volatile Matter Vitrinite Reflectance Coal Rank Marine Influence 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

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References

  1. Bailey, H.E., Glover, B.W., Holloway, S. and Young, S.R. (1995) Controls on coalbed methane prospectivity in Great Britain, in: M.K.G. Whateley and D.A. Spears (eds), European Coal Geology, Geological Society Special Publication 82, pp. 251–265.Google Scholar
  2. Beckett, J., Hamilton, D.S. and Weber, C.R. (1983) Permian and Triassic stratigraphy and sedimentation in the Gunnedah-Narrabri-Coonabarabran region, New South Wales Geological Survey Quarterly Notes 51, 1–16.Google Scholar
  3. Benedict, L.G., Thompson, R.R., Shigo, J.J.I1I and Aikman, R.P. (1968), Pseudovitrinite in Appalachian coking coals. Fuel 47, 125–143.Google Scholar
  4. Briel, J.M. and Savage, H.D. (1973) Properties of vitrinite concentrates of South African coals. Fuel 52, 3235.CrossRefGoogle Scholar
  5. Brown, H.R., Cook, A.C. and Taylor, G.H. (1964). Variations in the properties of vitrinite in isometamorphic coal, Fuel 43, 111–124.Google Scholar
  6. Bustin, R.M., Mastalerz, M. and Raudsepp, M. (1996) Electron-probe microanalysis of light elements in coal and other kerogen, International Journal of Coal Geology 32: 5–30.CrossRefGoogle Scholar
  7. Bustin, R.M., Mastalerz, M. and Wilks, K.R. (1993) Direct determination of carbon, oxygen and nitrogen content in coal using the electron microprobe, Fuel 72: 181–185.CrossRefGoogle Scholar
  8. Creedy, D.P. (1988) Geological controls on the formation and distribution of gas in British coal measure strata, International Journal of Coal Geology 10, 1–31.CrossRefGoogle Scholar
  9. Diessel, C.F.K. (1990) Marine influence on coal seams, Proceedings of 24th Symposium on Advances in the Study of the Sydney Basin, University of Newcastle, Newcastle, NSW, 33–40.Google Scholar
  10. Diessel, C.F.K. (1992a) Coal-Bearing Depositional Systems, Springer-Verlag, Berlin.CrossRefGoogle Scholar
  11. Diessel, C.F.K. (1992b) The problem of syn-versus post-depositional marine influence on coal composition. Proceedings of 26th Symposium on Advances in the Study of the Sydney Basin, University of Newcastle, Newcastle, NSW, 154–163.Google Scholar
  12. Fails, T. (1996) Coalbed methane potential of some Variscan foredeep basins, in R. Gayer and I. Harris (eds), Coalbed Methane and Coal Geology, Geological Society Special Publication 109, 13–26.Google Scholar
  13. Freudenberg, U., Lou, S., Schluter, R., Schutz, K. and Thomas, K. (1996) Main factors controlling coalbed methane distribution in the Ruhr District, Germany, in R. Gayer and I. Harris (eds), Coalbed Methane and Coal Geology, Geological Society Special Publication 109, 67–88.Google Scholar
  14. Gentzis, T. and Goodarzi, F. (1994) Reflectance suppression in some Cretaceous coals from Alberta, Canada, in P.K. Mukhopadhyay and W.G. Dow (eds), Vitrinite Reflectance as a Maturity Parameter: Applications and Limitations, ACS Symposium Series 570, American Chemical Society, Washington, pp. 93–110.CrossRefGoogle Scholar
  15. Gurba, L.W. (in preparation) Depositional and thermal factors affecting the three-dimensional coalification pattern in the Gunnedah Basin, New South Wales. PhD Thesis, University of New South Wales, Sydney.Google Scholar
  16. Gurba, L.W. and Ward, C.R. (1995) Coal rank variation in the Gunnedah Basin, in R.L. Boyd and G.A. McKenzie (eds), Proceedings of 29th Symposium “Advances in the Study of the Sydney Basin”, Department of Geology, University of Newcastle, N.S.W., 180–187.Google Scholar
  17. Gurba, L.W. and Ward, C.R. (1996) Reflectance anomalies in Permian coals of the Gunnedah Basin implications for maturation studies, in R.L. Boyd and G.A. McKenzie (eds), Proceedings of 30th Symposium “Advances in the Study of the Sydney Basin”, Department of Geology, University of Newcastle, N.S.W., 69–76.Google Scholar
  18. Gurba, L.W. and Ward, C. R. (1997) Chemical composition and coalification paths for vitrinite types in the Gunnedah Basin, New South Wales, Proceedings 7th New Zealand Coal Conference, Coal Research Limited, Wellington, New Zealand, 478–489.Google Scholar
  19. Gurba, L.W. and Ward, C.R. (1998) Vitrinite reflectance anomalies in high-volatile bituminous coals of the Gunnedah Basin, New South Wales, Australia, International Journal of Coal Geology 36, 111–140.CrossRefGoogle Scholar
  20. Hamilton, D.S. (1985) Deltaic depositional systems, coal distribution and quality, and petroleum potential, Permian Gunnedah Basin, New South Wales, Australia, Sedimentary Geology 45, 35–75.CrossRefGoogle Scholar
  21. Hamilton, D.S. (1991) Genetic stratigraphy of the Gunnedah Basin, N.S.W., Australian Journal of Earth Sciences 38, 95–113.CrossRefGoogle Scholar
  22. Hamilton, D.S. and Beckett, J. (1984) Permian depositional systems in the Gunnedah region, Geological Survey of New South Wales Quarterly Notes 55, 1–19.Google Scholar
  23. Hamilton, D.S. and Tadros, N.Z. (1994) Utlility of coal seams as genetic stratigraphic sequence boundaries in nonmarine basins: an example from the Gunnedah Basin, Australia, AAPG Bulletin 78 (2), 267–286.Google Scholar
  24. Hutton, A.C. and Cook, A.C. (1980) Influence of alginite on the reflectance of vitrinite from Joadja, NSWGoogle Scholar
  25. and some other coals and oil shales containing alginite, Fuel 59, 711–714.Google Scholar
  26. Jian, F.X. and Ward, C.R. (1993) Triassic depositional episode, in N.Z. Tadros (ed), The Gunnedah Basin, New South Wales, Geological Survey of New South Wales, Memoir Geology 12, 297–326.Google Scholar
  27. Kalkreuth, W. (1982) Rank and petrographic composition of selected Jurassic–Lower Cretaceous coals of British Columbia, Canada, Bulletin of Canadian Petroleum Geology 30 (2), 112–139.Google Scholar
  28. Kalkreuth, W. and McMechan, M. (1984) Regional pattern of thermal maturation as determined from coal-rank studies, Rocky Mountain Foothills and Front Ranges North of Grande Cache, Alberta-implications for petroleum exploration, Bulletin of Canadian Petroleum Geology 32 (3), 249–271.Google Scholar
  29. Levine, J.R. (1992) Oversimplifications can lead to faulty coalbed gas reservoir analysis, Oil and Gas Journal Nov. 23, 1992, 63–69.Google Scholar
  30. Mastalerz, M., Lamberson, M. and Bustin, M. (1994) Pseudovitrinite: chemical properties and origin, Geological Society of America Meeting Abstract.Google Scholar
  31. Mastalerz, M., Wilks, K.R. and Bustin, R.M. (1993) Variation in vitrinite chemistry as a function of associated liptinite content; a microprobe and FT-ir investigation, Organic Geochemistry 20 (5), 555–562.CrossRefGoogle Scholar
  32. McCartney, J.T. and Teichmüller, M. (1972) Classification of coals according to degree of coalification by reflectance of the vitrinite component, Fuel 51, 64–68.CrossRefGoogle Scholar
  33. Mukhopadhyay, P.K. and Dow, W.G. (eds) (1994) Vitrinite Reflectance as a Maturity Parameter: applications and limitations, ACS Symposium Series 570, American Chemical Society, Washington, 294 pp.CrossRefGoogle Scholar
  34. Newman, J. and Newman, N.A. (1982) Reflectance anomalies in Pike River coals: evidence of variability in vitrinite type, with implications for maturation studies and “Suggate rank”, New Zealand Journal of Geology and Geophysics 25, 233–243.CrossRefGoogle Scholar
  35. Price, L.C. and Barker, C.E. (1985) Suppression of vitrinite reflectance in amorphous rich kerogen–a major unrecognized problem, Journal of Petroleum Geology 8 (1), 59–84.CrossRefGoogle Scholar
  36. Raymond, A.C. and Murchison, D.G. (1991) Influence of exinitic macerals on the reflectance of vitrinite in Carboniferous sediments of the Midland Valley of Scotland, Fuel 70, 155–161.CrossRefGoogle Scholar
  37. Stach, E., Mackowsky, M-Th., Teichmüller, M., Taylor, G.H., Chandra, D. and Teichmüller, R. (eds) (1982) Stach’s Textbok of Coal Petrology, Gebruder Borntraeger, Berlin.Google Scholar
  38. Tadros, N.Z. (ed) (1993) The Gunnedah Basin New South Wales,Geological Survey of New South Wales, Memoir Geology, 12, New South Wales Department of Mineral Resources, Sydney, 550 pp.Google Scholar
  39. Tadros, N.Z. (1995) Gunnedah Basin, in C.R. Ward, H.J. Harrington, C.W. Mallett and J.W. Beeston (eds), Geology of Australian Coal Basins, Geological Society of Australia Coal Geology Group, Special Publication 1, 247–298.Google Scholar
  40. Teichmüller, M. (1987) Recent advances in coalification studies and their application to geology. In Scott, A.C. and Collinson, M.E. (eds), Coal and Coal-bearing Strata: Recent Advances, Geological Society Special Publication 32, Blackwell Scientific Publications, Oxford, 127–169.Google Scholar
  41. Teichmüller, M. and Teichmüller, R. (1982) The geological basis of coal formation, in E. Stach et al. (eds), Stach’s Textbook of Coal Petrology, Gebruder Bomtraeger Berlin, 5–87.Google Scholar

Copyright information

© Springer Science+Business Media Dordrecht 1999

Authors and Affiliations

  • Lila W. Gurba
    • 1
  • Colin R. Ward
    • 1
  1. 1.School of GeologyUniversity of New South WalesSydneyAustralia

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