Organic geochemical evaluation and hydrocarbon prospects of the Coniacian Awgu Formation, southern Benue Trough, Nigeria

  • Friday Daniel Onwe-MosesEmail author
  • Sunday Oliver Eze
  • Anthony Uwaoma Okoro
  • Okechukwu Pius Aghamelu
Original Paper


Samples of shale from the Coniacian Awgu Formation (southern Benue Trough, Nigeria) were subjected to petro-geochemical analyses in order to determine the hydrocarbon potentials of the formation. The results of the analyses, which included total organic carbon (TOC) content determination and Rock-Eval pyrolysis, show that TOC ranges from 0.53 to 2.91 wt% (with average value of 1.76 wt%), while the generative potential and the hydrogen index range from 0.56 to 3.42 mg HC/g (av. 1.93 mg HC/g) and 67 to 109 mg HC/g TOC (av. 94 mg HC/g TOC), respectively. The results also show vitrinite reflectance value that vary between 0.52 and 0.63% Ro (av. 0.60% Ro) and pyrolysis temperature 428 to 433 °C (av. 431 °C), and organic matter predominantly the type III. On the basis of the TOC, the average TOC (1.76 wt%) exceeds the minimum value of 0.50 wt% required for good hydrocarbon source rocks, and the other assessed parameters which indicate terrestrial-sourced organic matter, this study reveals that the Awgu Formation is a potential source rock, but with more capabilities to generate gas than oil. The overall thermal maturity stage of the kerogens in the formation is within the immature to early (threshold) mature.


Awgu Formation Hydrocarbon potential Organic geochemical analyses Source rock evaluation 



One of the authors gratefully acknowledges an anonymous colleague who made invaluable contributions in the review of the geology of the study area.


  1. Agagu OK, Adighije C (1983) Tectonic and sedimentation framework of the lower Benue Trough, Southeast Nigeria. J Afr Earth Sci 1:267–274Google Scholar
  2. Agagu OK, Ekweozor CM (1982) Source rock characteristics of Senonian shales in the Anambra syncline, southern Nigeria. J MinGeol 19:132–140Google Scholar
  3. Agagu OK, Fayose EA, Petters SW (1985) Stratigraphy and sedimentation in the Senonian Anambra Basin of eastern Nigeria. J Min Geol 22:25–36Google Scholar
  4. Akaegbobi IM (2005) The crabs eye-view of the organic sedimentological evolution of the Anambra basin Nigeria: hydrocarbon source potential and economic implications. Lecture paper, University of Ibadan, p.42Google Scholar
  5. Baskin DK (1997) Atomic H/C ratio of kerogen as an estimate of thermal maturity and organic matter conversion. AAPG Bull 81:1437–1450Google Scholar
  6. Benkhelil J (1989) The origin and evolution of the cretaceous Benue Trough (Nigeria). J Afr Earth Sci 8(2–4):251–282CrossRefGoogle Scholar
  7. Bordenave, E., Ph. Betrand, M.L., Brosse, E., Espitalie J., Houzay, J.P., Pradier B., Vandenbroucke U. and Walgenwitz F., (1993). Applied petroleum geochemistry, .ed, 1993Google Scholar
  8. Burke KC, Dessauvagie TF, Whiteman AJ (1972) Geologic history of the Benue Valley and adjacent areas. In: Dessauvagie TFJ, Whiteman AJ (eds) African Geology. Ibadan University Press, Ibadan, pp 187–205Google Scholar
  9. Cornford C (1986) Source rocks and hydrocarbons of the North Sea. In: Glennie KW (ed) Introduction to the petroleum geology of the North Sea, Oxford, U.K, pp 197–236Google Scholar
  10. Cratchley CR, Jones GP (1965) An interpretation of the geology and gravity anomalies of the Benue Valley, Nigeria. Overseas Geological Surveys Geophysical Paper, Vol. 1, H.M. Stationery Office, Norwich, pp 1–26Google Scholar
  11. Espitalié J, Madec M, Tissot B, Leplat P (1977) Source rock characterization method for petroleum exploration. Proceedings of the 9th Annual Offshore Technology Conference (OTC), Houston, pp 439–444Google Scholar
  12. Espitalié J, Deroo G, Marquis F (1985) La Pyrolyse Rock-Eval et ses applications. Première partie. Revue de l’IFP Energies nouvelles (French) - Oil Gas Sci Tech 40(5):563–578Google Scholar
  13. Fitton, J.G., (1983). Active versus passive continental rifting: evidence from the west African rift system. In Morgan, P. and Baker, B.H.., (Eds.), Processes of continental rifting. Tectonophysics. 94: 473–481Google Scholar
  14. Genik GJ (1993) Petroleum geology of cretaceous-tertiary rift basins in Niger, Chad and Central African Republic. AAPG Bull 77:1405–1434Google Scholar
  15. Geological Survey of Nigeria (1974) Geological map of Nigeria. Scale 1:2,000,000. Geological Survey of Nigeria, KadunaGoogle Scholar
  16. Gries RR, Clayton JL, Leonard C (1994) Geology, thermal maturation and source rock geochemistry in a volcanic covered basin, SanJuan sag, South Central Colorado. Am Assoc Pet Geol 81:1133–1160Google Scholar
  17. Hunt JM (1996) Petroleum geochemistry and geology. W.H. Freeman, New YorkGoogle Scholar
  18. Van Krevelen, D.W. (1961). Coal: typology–chemistry–physics constitution, Elsevier Science, Amsterdam, 514Google Scholar
  19. Longford FF, Blanc-Valleron (1990) Interpreting Rock–Eval pyrolysis data using graphs of pyrolyzable hydrocarbons vs. total organic carbon. AAPG Bull 74:799–804Google Scholar
  20. McCarthy K, Rojas K, Niemann M, Palmoswski D, Peters K, Stankiewicz A (2011) Basic petroleum geochemistry for source rock evaluation. Oilfield Review Summer. Sclumberger 23Google Scholar
  21. Murat, R.C., (1972). Stratigraphy and paleogeography of the cretaceous and lower tertiary in southern Nigeria. In: African geology, Dessauvagie T.J.F. And A.J. Whiteman (Eds.), University of Ibadan Press, Africa, 251–266Google Scholar
  22. Nwajide SC (2006) Outcrop analogies as a learning facility for subsurface practitioners: the value of geological field trips. Petroleum Train J 3:58–68Google Scholar
  23. Nwajide SC (2013) Geology of Nigeria’s sedimentary basin. CSS Bookshops, Lagos 565 ppGoogle Scholar
  24. Orajaka IP, Azubuike J, Obaje NG (2015) Petroleum geology for geoscientist. JB Xulon Press, FloridaGoogle Scholar
  25. Peters, K.E. and Cassa, M.R. (1994): Applied source rock geochemistry”. In: the petroleum system – from source to trap. L.B. Magoon and W.G. Dow (editors). AAPG Mem 60:93–117Google Scholar
  26. Peters KE (1986) Guidelines for evaluating petroleum source rock using programmed pyrolysis. AAPG Bull 70:318–329Google Scholar
  27. Petters SW (1977) Mid-Cretaceous paleoenvironments and biostratigraphy of the Benue Trough. Nigeria Geol Surv America Bull 89:151–154CrossRefGoogle Scholar
  28. Reyment RA (1965) Aspects of geology of Nigeria, University of Ibadan Press, 1969; ammonite biostratigraphy, continental drift and oscillatory transgressions; Nature Science, 2I: 137–140Google Scholar
  29. Selley A (1998) Elements of petroleum geology. 2nd Ed. Retrieved from: on 23/05/2016
  30. Simpson A (1954) The Nigerian coal field: the geology of parts of Onitsha, Owerri and Benue provinces. Geol Survey Nig Bull 24:85–85Google Scholar
  31. Tissot BP, Welte DH (1978) Petroleum formation and occurrence. Springer-Verlag, New York, p 521CrossRefGoogle Scholar
  32. Unomah GI, Ekweozor CM (1993) Petroleum source rock assessment of the Campanian Nkporo shale, lower Benue Trough, Nigeria. NAPE Bull 8:172–186Google Scholar
  33. Waples DG (1980) Time and temperature in petroleum formation: application of Lopatin’s method to petroleum exploration. Am Assoc Pet Geol Bull 64(6):916–926Google Scholar
  34. Whiteman AJ (1982) Nigeria: its petroleum geology, resources and potentials. (1) 176, (2) 238. Graham and Trotman, London, U.K.CrossRefGoogle Scholar

Copyright information

© Saudi Society for Geosciences 2019

Authors and Affiliations

  • Friday Daniel Onwe-Moses
    • 1
    Email author
  • Sunday Oliver Eze
    • 1
  • Anthony Uwaoma Okoro
    • 1
  • Okechukwu Pius Aghamelu
    • 2
  1. 1.Department of Geological SciencesNnamdi Azikiwe UniversityAwkaNigeria
  2. 2.Department of Physics, Geology and GeophysicsAlex Ekwueme Federal UniversityNdufu-AlikeNigeria

Personalised recommendations