Oil in the Niger delta: geology and geopolitics

Résumé du document

Niger Delta is extremely rich in terms of oil resources. Large progradation has lead to deposition of sand reservoirs and the sediment influx has lead to formation of growth faults and abundant traps. The heavy sedimentation has caused rapid subsidence and has allowed deep shales to enter the oil window and produce abundant accumulations. Unfortunately the history of the Nigerian oil industry has been riddled with conflict. The rich oil industry, with wealthy patrons and well paid foreign nationals, is contrasted by the countries low HDI, large span of different ethnic groups, dialects and religious beliefs and deplorably poor conditions among most of its people, accentuated by the pollution caused by the oil. As Emanuel Ndadozie said: "Oil is a curse which means only poverty, hunger, disease and exploitation" and this statement holds true for many Nigerians. Foreign influence is largely dominated by countries under the pretext of battling terrorism and poverty, and aiding in development, race for control of the black gold in the Gulf of Guinea.

Extraits

[...] Unfortunately corruption and greed, terrorism and civil strife, appear to be on the menu for Nigeria, in the worlds continued battle for the barrels. References Aigbedion, I., & Iyayi, S.E An appraisal of the Abura field. Int. J. Phys. Science 93-100. Beka, F. T., and Oti, M. N The distal offshore Niger Delta: frontier prospects of a mature petroleum province, in, Oti, M.N., and Postma, G., eds., Geology of Deltas: Rotterdam, A.A. Balkema, p Chautard S Géopolitique et Pétrole, Coll. [...]

[...] Virtually all oil and gas reservoirs can be found in the Agbada sandstones (Fig. 3). They are also nearly all structurally trapped and contained in rollover structures associated with growth-faults (Fig. 4). These features are thought to be the result of gravity acting on thick sediment deposits from the Niger Delta. Structural traps occur in other forms as well but growth faults are the most common, some stratigraphic traps also occur, mostly on the delta flanks (Beka and Oti, 1995; Tuttle et al., 1997). [...]

[...] Early sedimentation was dominated by evaporate deposition, which characterizes the rift to subsidence transition (Lehner & de Ruiter, 1977). Then the proto-Niger Delta built out which ended with Paleocene transgressions. From the Eocene onward regression ensued and the modern Niger Delta built out with accumulation of up to 10 km of sediment (Lambert- Aikhionbare & Shaw 1982; Tuttle et al., 1999). The sediments in the Niger Delta are considered to be a typical deltaic offlap sequence. At the continental margin deposits are largely sandy grading outward into marine clays. [...]

[...] http://www.pbs.org/newshour/indepth_ coverage/ africa/nigeria/oil.html Doust, H., and Omatsola, E Niger Delta, in, Edwards, J. D., and Santogrossi, P.A., eds., Divergent/passive Margin Basins, AAPG Memoir 48: Tulsa, American Association of Petroleum Geologists, p. 239-248. Evamy, B.D., Haremboure, J., Kamerling, P., Knaap, W.A., Molloy, F.A., and Rowlands, P.H Hydrocarbon habitat of Tertiary Niger Delta: American Association of Petroleum Geologists Bulletin, v p. 277-298. Guttschuss, E Nigeria's Delta blues - Nigeria's oil industry is beset with corruption. The result is higher oil prices and widespread human rights abuses. The Guardian. [...]

[...] The maximum depth to basement in the Niger delta is thought to be around 12 km (Weber, 1971). The boundaries of the delta are controlled by deep-seated faults along the Calabar and Benin Hinge-lines oriented ca NE/SW and NW/SE respectively (Fig. 2). Due to the rapid sedimentation growth faults developed in the Niger Delta (Weber, 1971). These structures have the shape of crescent and are usually concave out toward the basin with the focal point coinciding with the area of heaviest sedimentation. [...]