Journal of the Geological Society of India

, Volume 93, Issue 6, pp 713–726 | Cite as

Sequence Stratigraphic Interpretation of Late Cretaceous-Early Paleogene Sediments in the Central Part of Southern Anambra Basin, Nigeria

  • Samuel O. OnyekuruEmail author
  • Alexander I. OparaEmail author
  • Ikechukwu O. Njoku
  • Emmanuel O. Bassey
  • Cyril E. Ukaonu
Research Articles


The identification of additional hydrocarbon reserves to buffer pressure from increasing energy demands in Nigeria necessitated the application of sequence stratigraphic framework in the analysis of sedimentary successions in the central portion of southern Anambra basin. Wireline logs and biofacies data from three exploratory wells (S-1, S-2 and S-3) were used for the study. The stratigraphy of the study area observed from the three wells showed an overall regressive succession with short-lived transgressions. Lithofacies associations deduced from well log signatures defined four lithostratigraphic units: The Mamu and Ajali formations of kate Maastrichtian age; the Nsukka Formation of kate Maastrichtian — Danian age and Imo Formation of Paleocene age. The study further used the depositional sequence model to identify sequences and accompanying systems tracts that are bounded at the top and bottom by unconformities. Dating of identified key stratigraphic surfaces was achieved by correlating chronostratigraphic biofacies data to third order cycle charts. Correlation across the three wells highlighted spatial distributions of reservoirs and some useful stratigraphic and structural discontinuities that could form hydrocarbon traps. It also showed profitable stratigraphic surfaces that would aid basin-wide correlation for improved horizon(s) mapping and hydrocarbon prospectivity in the Anambra basin. Erosional unconformities identified in the wells that correlated with major drops in global sea level, fingerprinted the influence of eustacy on sedimentation and sequence development. Other factors such as subsidence and sediment supply have direct relationships to the identified structures (faults) which also initiated the accommodation created for sedimentation in the study area.


Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.



We are grateful to the management of Shell Petroleum Development Company (SPDC), Port Harcourt and the Department of Petroleum Resources (DPR), Nigeria for providing the raw data used in the study.


  1. Agumanu, A.E. (1993) Sedimentology of Owelli Sandstone (Campano-Maastrichtian) Benue Trough. Jour. Min. Geol., v.29, pp.21–35.Google Scholar
  2. Akaegbobi, I.M. and Boboye (1999) Textural, structural features and microfossil assemblage relationships as a delineating criteria for the stratigraphic boundary between Mamu Formation and the Nkporo shale within the Anambra Basin, Nigeria. NAPE Bull., no.14, pp.176–193.Google Scholar
  3. Amajor, L.C. (1987) Paleocurrent, petrography and provenance analyses of the Ajali Sandstone (Upper Cretaceous), Southeastern Benue Trough, Nigeria. Sed. Geol., v.54, pp.47–60.CrossRefGoogle Scholar
  4. Avbovbo, A.A. and Ayoola, O. (1981) Petroleum prospects of southern Nigeria–s Anambra Basin. Oil Gas Jour., v.79, pp.334–347.Google Scholar
  5. Akaegbobi, I.M. and Schmitt, M. (1998) Organic Facies, Hydrocarbon Source Potential and Reconstruction of the Depositional Paleoenvironment of the Campano-Maastrichtian Nkporo Shale in the Cretaceous Anambra Basin. Nigerian Assoc. Petrol. Explor. Bull., v.13(1), pp.1–19.Google Scholar
  6. Benkhelil, J. (1982) Benue trough and Benue Chain. Geol. Mag., v. 119, pp.155–168.CrossRefGoogle Scholar
  7. Burke, E. (1972) Longshore drift submarine canyons and submarine fans in development of Niger Delta. AAPG Bull., v.56, pp.1975–1983.Google Scholar
  8. Catuneanu, O. (2006) Principles of Stratigraphy. Elsevier, Amsterdam, Netherland, 375p.Google Scholar
  9. Ekweozor, C.M. (2005) Searching for Petroleum in the Anambra Basin. In: Okogbue, C.O. (Ed.), Hydrocarbon Potentials of the Anambra Basin. Great AP Express Publishers Ltd., Nigeria, pp.1–110.Google Scholar
  10. Emery, D. and Myers, K.J. (1996) Sequence Stratigraphy. Blackwell Science Oxford, Oxford, UK., 297p.CrossRefGoogle Scholar
  11. Grant, N.K. (1971) South Atlantic, Benue Trough and gulf of Guinea Cretaceous triple junction. Bull. Geol. Soc. Amer., v.82, pp.2295–2298.CrossRefGoogle Scholar
  12. Haq, B.U., Hardenbol, J. and Vail, P.R. (1988) Mesozoic and Cenozoic Chronostratigraphy and Cycles of Sea-Level Change. In: Wilgus, C.K., B.S. Hastings, C.G. St. C. Kendall, H.W. Posamentier, C.A. Ross and J.C. Van Wagoner (Eds.), Sea-Level Changes: An Integrated Approach, Vol. 42. SEPM Publication, USA, pp.72–108.Google Scholar
  13. Hardenbol, J., Thierry, J., Farley, M.B., Jacquin, T., De Graciansky, P.C. and Vail, P.R. (1998) Mesozoic-Cenozoic Sequence Chronostratigraphic Framework of European Basins. In: De Graciansky, P.C., J. Hardenbol, T. Jacquin and P.R.J. Vail (Eds.), Mesozoic and Cenozoic Sequence Stratigraphy of European Basins. SEPM, Tulsa, Oklahoma, v.60, pp.3–13.CrossRefGoogle Scholar
  14. Hettinger, R.D. (1995) Sedimentological descriptions and depositional interpretations, in sequence stratigraphic context, of two 300-meter cores from the upper cretaceous straight Cliffs Formation, Kaiparowits Plateau, Kane County, Utah. USGS Bull., no, 2115-A., pp.1–32.Google Scholar
  15. Hoque, M. and Ezepue, M.C. (1977) Petrology and paleography of the Ajali sandstone. Jour. Sed. Petrol., v.46, pp.579–594.Google Scholar
  16. Kendall, C.G and Pomar, L. (2005) System tract bounding surfaces, lithofacies, geometric hierarchies and stacking patterns: Keys to shallow water carbonate interpretation. AAPG Bull., v.89.Google Scholar
  17. Mode, A.W. and Onuoha, K.M. (2001) Organic matter evaluation of the Nkporo Shale, Anambra basin, from wireline logs. Global Jour. Appld. Sci., v.7, pp.103–107.Google Scholar
  18. Murat, C. (1972) Stratigraphy and Paleogeography of the Cretaceous and Lower Tertiary in South-Eastern Nigeria. In: Dessauvagie, T.F.J. and A.J. Whiteman (Eds.), African Geology, University of Ibadan Press, Nigeria, 251–266.Google Scholar
  19. Nwajide, C.S. (2005) Anambra Basin of Nigeria: Synoptic Basin Analysis as a Basis for Evaluating its Hydrocarbon Prospectivity. In: Okogbue, C.O. (Ed.), Hydrocarbon Potentials of the Anambra Basin, Great AP Express Publishers Limited, Nigeria, pp.1–46.Google Scholar
  20. Nwajide, C.S. and Reijers, T.J.A. (1996) Sequence architecture in outcrops: Examples from the Anambra Basin Nigeria. NAPE Bull., no.11, pp.23–32.Google Scholar
  21. Nwajide, C.S. and Reijers, T.J.A. (1997) Sequence architecture of the Campanian Nkporo and the Eocene Nanka Formations of the Anambra basin, Nigeria. NAPE Bull., no.12, pp.75–87.Google Scholar
  22. Obaje, N.G., Ulu, O.K., and Petters, S.W. (1999) Biostratigraphic and geochemical controls of the hydrocarbon prospects in the Benue Trough and the Anambra Basin Nigeria. NAPE Bull., no.14, pp.18–54.Google Scholar
  23. Obi, G.C. (2000) Depositional model for the Campano-Maastrichtian Anambra Basin southern Nigeria. Ph.D. Thesis, University of Nigeria, Nigeria.Google Scholar
  24. Obi, G.C., Okogbue, C.O. and Nwajide, C.S. (2001) Evolution of the Enugu cuesta: A tectonically driven erosional process. Global Jour. Pure Appld. Sci., v.7, pp.321–330.Google Scholar
  25. Okezie, C.E. (1974) Geological map of Nigeria. Geological Survey of Nigeria.Google Scholar
  26. Onyekuru, S.O. and Iwuagwu, C.J. (2010) Depositional Environments and sequence stratigraphic interpretation of the Campano-Maastrichtian Nkporo Shale Group and Mamu Formation exposed at Leru-Okigwe axis, Anambra Basin, Southeastern Nigeria. Australian Jour. Basic Appld. Sci., v. 4(12), pp.6623–6640.Google Scholar
  27. Onyekuru, S.O., Ibelegbu, E.C., Iwuagwu, J.C., Essien, A.G. and Akaolisa, C.Z. (2012) Sequence stratigraphic analysis of “XB Field”, Central Swamp Depobelt, Niger Delta Basin, Southern Nigeria. Int. Jour. Geosci., v.3, pp.237–257.CrossRefGoogle Scholar
  28. Petters, S.W. (1978) Stratigraphic evolution of the Benue trough and its implications for the upper cretaceous paleogeography of the West Africa. Jour. Geol., v.86, pp.311–322.CrossRefGoogle Scholar
  29. Vail, P.R. (1987) Seismic Stratigraphic Interpretation Using Sequence Stratigraphy. Part 1: Seismic Stratigraphy Interpretation Procedure. In: Bally, A.W. (Ed.), Atlas of Seismic Stratigraphy, AAPG Studies in Geology, Tulsa, Oklahoma, v.27, pp.1–10.Google Scholar
  30. Vail, P.R., Mitchum, R.M. and Thompson, S.III (1977) Seismic Stratigraphy and Global changes of Sea Level, part 3: Relative Changes of Sea Level from Coastal Onlap. In: Payton, C.W. (Ed.), Seismic Stratigraphy Applications to Hydrocarbon Exploration. AAPG, USA, pp.63–97.Google Scholar
  31. Vail, P.R. and Wornadt, W. W. (1990) Well Log Seismic Sequence Stratigraphy: An Integrated Tools for the 90–s. In: Armentrout, J.M. and B.F. Perkins (Eds.), Sequence Stratigraphy as an Exploration Tool: Concepts and Practices from the Gulf Coast. Earth Enterprises Inc., Austin, Houston, TX, pp.379–388.CrossRefGoogle Scholar
  32. Van Wagoner, J.C., Posamentier, H.W., Mitchum, R.M., Vail, P.R., Sarg, J.F., Loutit, T.S. and Hardenbol, J. (1988) An Overview of Sequence Stratigraphy and Key Definitions. In: Wilgus, C.W. (Ed.), Sea Level Changes: An Integrated Approach. Society of Economic Paleontologists and Mineralogists, USA, Vol. 42, pp.39–45.CrossRefGoogle Scholar
  33. Van Wagoner, J.C. (1990) Siliciclastic sequence stratigraphy in well logs, cores and outcrops: Concept for high-resolution correlation of time and facies. American Association of Petroleum Geologists, AAPG Methods in Exploration Series, No. 7, 55p.Google Scholar
  34. Whiteman, A.J. (1982) Nigeria, Its Petroleum Geology, Resources and Potentil. Graham and Trotman, London, 394p.CrossRefGoogle Scholar

Copyright information


Authors and Affiliations

  • Samuel O. Onyekuru
    • 1
    Email author
  • Alexander I. Opara
    • 1
    Email author
  • Ikechukwu O. Njoku
    • 1
  • Emmanuel O. Bassey
    • 2
  • Cyril E. Ukaonu
    • 3
  1. 1.Department of GeologyFederal University of TechnologyOwerriNigeria
  2. 2.First Exploration and Petroleum Development Company LimitedLagosNigeria
  3. 3.Southsea Petroleum ServicesPort HarcourtNigeria

Personalised recommendations