ABSTRACT The aim of this research work was to report a facies analysis of the N’Kappa formation, identified the clay minerals present in those facies and evaluate their oil potential. For that to be done, Lithostratigraphic descriptions were performed on three natural outcrops chosen in three different localities of the northern border of Douala sedimentary basin. Ten shaly samples were then collected on those outcrops and submit to X ray diffraction and Rock-Eval pyrolysis. Lithologically, the N’Kappa formation is made up of dark to grey shales and fine to coarse sandtones. The mineralogic content of the shales is made up of Kaolinite, dickite, low quartz and vaterite. Those shaly facies present high amount of immature organic matter (average TOC content around 2%). The petroleum potential is fair to poor (average S2 for all the samples around 3.33 mg HC/g of rock) though some samples (M1 and M2) presenting a good petroleum potential up to 6.62 kg HC/t of rock and 6.44 kg HC/t of rock respectively. They have undergone a low degree of diagenesis (early to burying diagenesis). This is evidenced by the predominance of kaolinite and dickite, low quartz and vaterite which are minerals stable at low temperature.
Cite this paper
P. Kenfack, P. Njike Ngaha, G. Ekodeck and G. Ngueutchoua, "Mineralogic Characterization and Petroleum Potential of Clays (Shales) of the N’Kappa Formation (Paléocene-Eocene) in the Douala Sedimentary Sub-basin (South-West Cameroon)," International Journal of Geosciences, Vol. 3 No. 4, 2012, pp. 696-709. doi: 10.4236/ijg.2012.34070.
 F. Solger, “Die Fossilien der Mungokreide in Kamerun und irhe Geologische Bedeutung,” Beitr. Geol. Kamerun, 1904, pp. 85-242.
 F. Solger, “Die petroleum funde am Mungo,” Bohrtecniker zeit, Wien, t. 11, 14, 1904 b. 12p.
 S. F. Tamfu, M. Batupe, R. J. Pauken and D. C. Boatwright, “Geological setting, stratigraphy and hydrocarbon habitat of the Douala Basin, Cameroon,” American Association of Petroleum Geologists Bulletin, Vol. 79, No. 13, 1995, p. 95.
 P. Menzel, “Fossile Pflanzenreste aus den Mungo-schiten in Kamerun,” Abh. K. Preuss Geol. Landes., Neue Folge, Vol. 62, 1909, pp. 399-404.
 T. Vries, “Research Mission on Hydrocarbons in Cameroon Conducted between 1935-1936,” General Report, Department of Mines, Cameroon, 1936, 72 p.
 E. Marchesini and B. Frasson, “Report on the Geological Survey of French Cameroon, December 1951-March 1952,” Standard Oil C, New Jersey, 1952, 14 p.
 D. Reyre, “Geological History of the Douala Basin (Cameroon),” Post-Cambrian Coastal Sedimentary Basins of West Africa, Part III, Micropaleontology Conference Dakar, African Association of Geological Services, Paris, 1964, 18 p.
 D. Reyre, “Geological History of the Douala Basin,” In: D. Reyre, Ed., Symposium on the Sedimentary Basins of the African Coast, African Association of Geological Services, IUGS, Paris, 1966, pp. 143-161.
 Y. C. Belmonte, “Stratigraphy of the Cameroon Sedimentary basin,” Proceedings of the 2nd West African Micropaleontological Colloquium, Ibadan, 18 June-1 July 1966, pp. 7-24.
 M. Salard-Cheboldaeff, “Evidence of Oligocene in Cameroon Coastal Sedimentary Basin, According to Palynological Data,” Report of Science Academy, Series D, Paris, 1976, pp. 41-43.
 M. Salard-cheboldaeff, “Paléopalynology Cameroon Littoral Sedimentary Basin in Its Relations with the Stra- tigraphy and Paleoecology,” PhD Thesis, Pierre and Marie Curie University, Paris, 1977, 262 p.
 M. Salard-Cheboldaeff, “Tertiary Pollens from Cameroon Reported to the Family Rubiaceae,” Proceedings of the 6th African Micropaleontology Colloquium, Annual of Mines and Geology, Vol. 3, No. 28, 1980, pp. 279-289.
 P. R. Njike Ngaha, “Contribution to the Geological, Stratigraphic and Structural Study of the Atlantic Border of Cameroon Sedimentary Basin,” PhD Thesis, University of Yaounde, Yaounde, 1984, 131 p.
 P. R. N. Ngaha and S. M. E. Belinga, “Evidence of Two Distinct Structural Domains in the Southwest of Cameroon Using the Photo-Interpretation Methods,” Annals of the faculty of Science, Earth Science, Series IV, Vol. 1, No. 3-4, 1984, pp. 69-81.
 P. R. N. Ngaha and S. M. E. Belinga, “The Diachronism of the Basal Sandstone , Paleoenvironment and the Role of the Opening of the South Atlantic,” Annals of the Faculty of Sciences, Earth Science, Series IV, Vol. 1, No. 3-4, 1987, pp. 103-119.
 R. J. Pauken, J. M. Thompson, J. R. Schuman and J. C. Cooke, “Geology of the Douala Basin, Offshore Cameroon,” Am. Assoc. Petr. Geol. Bull., Vol. 75, No. 3, 1991, pp. 651-652.
 W. C. Ackerman, D. C. Boatwright, B. M. Burwood, D. Van Lerberche, E. Bondjo, S. F. Tamfu and D. Ovono, “Geochemical Analysis of Selected Hydrocarbon Samples in the Douala Basin, Cameroon. Implications for an Oil-Prone Source Rock,” American Association of Petroleum Geologists Bulletin, Vol. 77, No. 9, 1993, p. 1604.
 S. F. Tamfu, M. Batupe, R. J. Pauken and D. C. Boatwright,“Geological Setting, Stratigraphy and Hydrocarbon Habitat of the Douala Basin, Cameroon,” American Association of Petroleum Geologists Bulletin, Vol. 79, No. 13, 1995, p. 95
 P. R. N. Ngaha, “Palynostratigraphy and Reconstruction of the Cretaceous Paleoenvironments of the East of Douala Sedimentary Basin (Cameroon),” PhD Thesis, University of Yaounde I, Yaounde, 2005, 259 p.
 A. J. V. Garcia, “Paleogeographia de Nordeste Brasileiro no jurassico superior-cretaceo inferior Geociensias,” Vol. 10, 1991, pp. 37-56.
 S. R. Lawrence, S. Munday and R. Bray, “Regional Geology and Geophysics of the Eastern Gulf of Guinea (Niger Delta to Rio Muni),” The Leading Edge, 2002, pp. 1113-1117.
 F. R. Nguene, S. F. Tamfu, J. P. Loule and C. Ngassa, “Palaeoenvironments the Douala and Kribi/Campo SubBasins, in Cameroon, West Africa,” In: R. Curnelle, Ed., African Geology, 1st Colloquium on Stratigraphy and Paleogeography of West African Sedimentary Basins, 2nd Colloquium of African Micropaleontology, Libreville, 1991, Boussens, Elf Aquitaine, 1992, pp. 129-139.
 R. J. Pauken, “Sanaga Sud Field, Offshore Cameroon, West Africa,” In: M. T. Halbouty, Ed., Giant Oil and Gas Fields of the Decade 1978-1988, Am. Assoc. Petr. Geol. Mem., Vol. 54, 1990, pp. 217-230.
 J. D. Hedberg, “A Geological Analysis of the Cameroon Trend,” PhD Dissertation, Princeton University, Princeton, 1969, 188 p.
 K. O. Emery, E. Uchupi, J. Phillips, C. Bowin and J. Mascle, “Continental Margin of Western Africa: Angola to Sierra Leone,” American Association of Petroleum Geologists Bulletin, Vol. 59. No. 12, 1975, pp. 2209-2265.
 J. M. Regnoult, “Cameroon Geological Synthesis,” Department of Mines and Geology, Yaounde, 1986, 119 p.
 T. J. A. Reijers and S. W. Petters, “Depositional Environments and Diagenesis of Albian Carbona tes on the Calabar Flank, SE Nigeria,” Journal of Petroleum Geology, Vol. 10, 1987, pp. 283-294.
 J. Benkhelil, P. Giresse, C. Poumot and G. Ngueutchoua, “Lithostratigraphic, Geophysical and Morpho-Tectonic Studies of the South Cameroon Shelf,” Marine and Petroleum Geology, Vol. 19, 2002, pp. 499-517.
 A. H. Brink, “Petroleum Geology of Gabon Basin,” AAPG Bulletin, Vol. 58, 1974, pp. 215-235.
 D. Reyre, “Remark on the Evolution of African Atlantic Coastal Sedimentary Basins,” Bulletin of the French Geological Society, Vol. 36, 1984, pp. 1041-1059.
 P. Teisserenc and J. Villemin, “Sedimentary Basin of Gabon-Geology and Oil Systems,” In: J. D. Edwards, P. A. Santogrossi, Eds., Divergent/Passive Margin Basins, Vol. 46. American Association of Petroleum Geologists Mem 48, 1989, pp. 117-199.
 K. O. Emery, E. Uchupi, J. Phillips, C. Bowin and J. Mascle, “Continental Margin of Western Africa: Angola to Sierra Leone,” American Association of Petroleum Geologists Bulletin, Vol. 59, No. 12, 1975, pp. 2209-2265.
 J. H. Natland, “Composition, Provenance, and Diagenesis of Cretaceous Clasti Sediments Drilled on the Atlantic Continental Rise off Southern Africa, DSDP Site 361— Implications for the Early Circulation of the South Atlantic/Nit,” Rep. DSDP 40, 1978, pp. 1025-1061.
 H. M. Bolli, et al., Init. Rep. DSDP 40, 1978, p. 1078.
 B. Tissot, G. Demaison, P. Masson, J. R. Delteil and A. Conbaz, “Paleoenvironment and Petroleum Potential of Middle Creataceous Black Shales in Atlantic Basin,” AAPG Bulletin, Vol. 64, 1980, pp. 2051-2063.
 P. V. Zalan, E. P. Nelson, J. E. Warme and T. L. Davis, “The Piaui Basin: Rifting and Wrenching in an Equatorial Atlantic Transform Margin,” In: K. T. Biddle and N. C. Blick, Eds., Strike-Slip Deformation, Basin Formation, and Sedimentation: SEPM Spec. Pub. 37, 1985, pp. 177-192. HUdoi:10.2110/pec.85.37.0177U
 E. A. M. Koutsoukos, M. R. Mello, C. D. A. Filho, M. B. Hart and J. R. Maxwell, “The Upper Aptian-Albian Succession of the Sergipe Basin, Brazil: An Integrated Paleoenvironmental Assessment,” AAPG Bulletin, Vol. 75, 1991, pp. 479-498
 E. Nyong and R. Ramanathan, “A Record of Oxygen Deficient Paleoenvironments in the Cretaceous of the Calabar Flank, SE Nigeria,” Journal of African Earth Sciences, Vol. 3, 1985, pp. 455-460.
 J. P. Turner, “Gravity-Driven Structures and Rift Basin Evolution: Rio Muni Basin, Offshore West Africa,” American Association of Petroleum Geologists Bulletin, Vol. 79, No. 8, 1995, pp. 1138-1158.
 J. P. Turner, B. R. Rosendahl and P. G. Wilson, “Structure and Evolution of an Obliquely Sheared Continental Margin: Rio Muni, West Africa,” Tectonophysics, Vol. 374, 2003, pp. 41-55.
 M. J. Ntamak-Nida, S. Bourquin, J. C. Makong, F. Baudin, J. E. Mpesse, C. I. Ngouem, P. B. Komguem, and G. M. Abolo, “Sedimentology and Sequence Stratigraphy from Outcrops of the Kribi-Campo Sub-Basin: Lower Mundeck Formation (Lower Cretaceous, Southern Cameroon),” Journal of African Earth Sciences, Vol. 58, No. 1, 2010, pp. 1-18. doi:10.1016/j.jafrearsci.2010.01.004U
 J. C. Dumort, “Explanatory Notice of the sheet Douala West. Geological Recognition Map at scale 1/500,000,” Department of Mines and Geology, Cameroon, 1968, 69 p.
 J. B. Meyers, B. R. Rosendahl, H. Groschel-Becker, J. A. Austin and P. A. Rona, “Deep Penetrating MCS Imaging of the Rift-to-Drift Transition, Offshore Douala and North Gabon Basins, West Africa,” Marine and Petroleum Geology, Vol. 13, No. 7, 1996, pp. 791-835.
 J. Espitalié, G. Deroo and F. Marquis, “La pyrolyse Rock Eval et ses applications,” Rev. l’Inst. Fr. Pet. 40, 1985, p. 755-784.
 L. B. Magoon and W. G. Dow, “The Petroleum System,” In: L. B. Magoon, W. G. Dow, Eds., The Petroleum System: From Source to Trap, American Association of Petroleum geologist Memoirs, Vol. 60, 1994, pp. 3-24.
 B. P. Tissot and D. H. Welte, “Petroleum Formation and Occurrence,” 2nd Edition, Springer-Verlag, Berlin, 1984, 699 p.
 M. L. Bordenave, “Applied Petroleum Geochemistry,” Editions Technip, 1993, 524 p.
 A. Riboulleau, “Geochemistry of Black Shales of the Upper Jurassic of the Russian Platform. Sedimentation and Preservation of Organic Matter,” PhD Thesis, Paris VI University, Paris, 2000, 262 p.
 Y. Héroux, A. Chagnon and R. Bertrand, “Compilation and Correlation of Major Thermal Maturation Indicators,” American Association of Petroleum Geologists Bulletin, Vol. 63, 1979, pp. 2128-2144.
 S. D Burley and H. R. Worden, “Sandstone Diagenesis: Recent and Ancient,” John Wiley & Sons, New York, 2003, 649 p.
 D. G. Segonzac, “The Transformation of Clay Minerals during Diagenesis and Low Grade Metamorphism: A Review,” Sedimentology, Vol. 15, 1970, pp. 281-346.
 V. D.Shutov, A. V.Aleksandrova and S. A. Losievskaya, “Genetic Interpretation of the Polymorphism of the Kaolinite Group in Sedimentary Rocks,” Sedimentology, Vol. 15, 1970, pp. 69-82.
 M. E. Ndonwie, “Petrophysical Characterization of Petroleum Reservoirs and Source Beds of the Batanga Sub-Block, Kribi-Campo Sub-Basin, Cameroon,” AAPG Annual Convention, Abstract, 2007, 1 p.
 M. J. Ntamak-Nida, F. Baudin, J. Schnydern, J. C. Makong, P. B. O. Komguem and G. M. Abolo, “Depositional Environments and Characterization of the Organic Matter of the Lower Mundeck Formation (Barremian?-Aptian) of the Kribi-Campo Sub-Basin (South Cameroon): Implica- tions for Petroleum Exploration,” Journal of African Earth Sciences, Vol. 51, 2008, pp. 207-219.
 M. A. Pasley, E. N. Wilson, V. A. Abreu, M. G. P. Bran- dao and A. S. Telles, “Lower Cretaceous Stratigraphy and Source Rock Distribution in Pre-Salt Basins of the South Atlantic. Comparison of Angola and Southern Brazil,” American Association of Petroleum Geologists Bulletin, Vol. 82, No. 10, 1998, p. 1949.
 S. E. Brice, M. D. Cochran, G. Pardo and A. D. Edwards, “Tectonics and Sedimentation of the South Atlantic Rift Sequence, Cabinda, Angola,” In: J. S. Watkins, C. L. Drake, Eds., Studies in Continental Margin Geology, American Association of Petroleum Geologist Memory, Vol. 34, 1982, pp. 5-18.
 N. B. Schoellkopf and B. A. Patterson, “Petroleum Systems of Offshore Cabinda, Angola,” In: M. R. Mello and B. J. Katz. Eds., Petroleum Systems of South Atlantic Margins, Am. Assoc. Petr. Geol. Mem., Vol. 73, 2000, pp. 361-376.
 S. Baudouy and C. Legorjus, “Sendji Field—People’s Republic of Congo, Congo Basin,” In: N. H. Foster and E. A. Beaumont, Eds., Treatise of Petroleum Geology, Atlas of Oil and Gas Fields—Structural Traps V: Tulsa, Okla, Am. Assoc. Petr. Geol., 1991, pp. 121-149.
 M. M. Mounguengui, F. Baudin, J. Lang and O. Jocktane, “Paleoenvironments and Characterization of Oil Source Rocks of Pre-Saliferous Series of the Interior of Gabon Basin,” Report of the Academy of Science, Paris, 2003, pp. 327-334.
 J. P. Turner, “Detachment Faulting and Petroleum Prospectivity in the Rio Muni Basin, Equatorial Guinea, West Africa,” In: N. R. Cameroon, R. H. Bate and V.-S. Clure, Eds., The Oil and Gas Habitats of the South Atlantic, Vol. 153, Geological Society Special Publications, 1999, pp. 303-320.