Application of model-based inversion technique in a field in the coastal swamp depobelt, Niger delta

  • Authors

    • Okoli Austin Department of Geology, Federal University of Technology, Owerri
    • Onyekuru Samuel I. Department of Geology, Federal University of Technology, Owerri
    • Okechukwu Agbasi University of Uyo, Uyo, Akwa Ibom State, Nigeria
    • Zaidoon Taha Abdulrazzaq Ministry of Science and Technology/ Space Directorate and Communication.
    2018-04-22
    https://doi.org/10.14419/ijag.v6i1.10124
  • Amplitude, Reflectivity, Acoustic Impedance, Model-based Inversion, Poisson’s ratio.

  • Considering the heterogeneity of the reservoir sands in the Niger Delta basin which are primary causes of low hydrocarbon recovery efficiency, poor sweep, early breakthrough and pockets of bypassed oil there arises a need for in-depth quantitative interpretation and more analysis to be done on seismic data to achieve a reliable reservoir characterization to improve recovery, plan future development wells within field and achieve deeper prospecting for depths not penetrated by the wells and areas far away from well locations. An effective tool towards de-risking prospects is seismic inversion which transforms a seismic reflection data to a quantitative rock-property description of a reservoir. The choice of model-based inversion in this study was due to well control, again considering the heterogeneity of the sands in the field. X-26, X-30, and X-32 were used to generate an initial impedance log which is used to update the estimated reflectivity from which we would obtain our inverted volumes. Acoustic impedance volumes were generated and observations made were consistent with depth trends established for the Niger Delta basin, inverted slices of Poisson impedances validated the expected responses considering the effect of compaction. This justifies the use of inversion method in further characterizing the plays identified in the region.

  • References

    1. [1] Oldenburg, D.W., Levy, S., and Stinson, K., 1984, Root-mean-square velocities and recovery of the acoustic impedance: Geophysics 49, pp1653-1663. https://doi.org/10.1190/1.1441573.

      [2] Sheriff, R.E., 2002. Encyclopedic dictionary of Applied Geophysics, 4th edition: Society of Exploration Geophysicists, Tulsa, Oklahoma. https://doi.org/10.1190/1.9781560802969.

      [3] PendreL J., 2006, Seismic inversion- A critical tool in reservoir characterization: Scandinavian oil-gas magazine, 5/6, 19-22.

      [4] Evamy, B.D., Haremboure, J., Kamerling, P., Knaap, W.A., Molloy, F.A., and Rowlands, P.H., 1978, Hydrocarbon habitat of Tertiary Niger Delta: American Association of Petroleum Geologists Bulletin, v. 62, p. 277-298.

      [5] Kulke, H., 1995, Nigeria, in, Kulke, H., ed., Regional Petroleum Geology of the World. Part Ii: Africa, America, Australia and Antarctica: Berlin, Gebriider Borntraeger, p. 143-172.

      [6] Edwards, J.D., and Santogrossi, P.A., 1990, Summary and conclusions, 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.

      [7] Weber, K. J., and Dakouru, E.M., 1975, Petroleum geology of the Niger Delta: Proceedings of the Ninth World Petroleum Congress, volume 2, Geology: London, Applied Science Publishers, Ltd., p. 210-221.

      [8] Beka, F. T., and Oti, M. N., 1995. 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. 237-241.

      [9] Ejedawe, J.E., 1981, Patterns of incidence of oil reserves in Niger Delta Basin: American Association of Petroleum Geologists, v. 65, p.1574-1585.

      [10] Doust, H., and Omatsola, E., 1990, 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.

      [11] Tuttle, M.L.W., Charpentier, R.R., and Brownfield, M.E., 1999, The Niger Delta petroleum system: Niger Delta province, Cameroon, and Equato rialGuinea, Africa: http://greenwood.cr.us gs. gov/energy/ Won dEnergy/O F99-5 0H/ChapterA.htm#TOP.

      [12] SPDC 2005, Pre-stack time migration of Cawthorne channel, Akasa, Krakama (CAKK3D)

      [13] Olowokere M. T. and Ojo J. S. (2011), Porosity and Lithology Prediction in Eve Field, Niger Delta Using Compaction Curves and Rock Physics. International Journal of Geosciences, Vol 2, pp 366-372. https://doi.org/10.4236/ijg.2011.23039.

      [14] Shuey, R.T., 1985, A simplification of the Zoeppritz equations: Geophysics, 50, 609 — 614. https://doi.org/10.1190/1.1441936.

      [15] Castagna, J.P., and Swan, H.W., 1997, Principle of AVO cross plotting: The Leading Edge, 04, 337 — 342. https://doi.org/10.1190/1.1437626.

      [16] Hilterman F. J., 2001, Seismic Amplitude Interpretation: Distinguished Instructor Series, No. 4, Society of Exploration Geophysicists. https://doi.org/10.1190/1.9781560801993.

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  • How to Cite

    Austin, O., Samuel I., O., Agbasi, O., & Abdulrazzaq, Z. T. (2018). Application of model-based inversion technique in a field in the coastal swamp depobelt, Niger delta. International Journal of Advanced Geosciences, 6(1), 122-126. https://doi.org/10.14419/ijag.v6i1.10124