Determination of rock elastic parameters using VP/VS relation-ship for escravos area, Niger delta, Nigeria

  • Authors

    • Tobiloba Ajayi Obafemi Awolowo University
    • Abraham Adepelumi Obafemi Awolowo University
    • Christain Agih Obafemi Awolowo University
    2014-11-03
    https://doi.org/10.14419/ijag.v2i2.3490

  • Abstract

    The elastic properties of sedimentary rocks in the Escravos area, Niger delta, Nigeria, have been computed for six boreholes drilled to a maximum of 22 m. Compressional wave (Vp), Shear wave (Vs) velocities and density (?) values were computed for the lithologies at the six different boreholes. The elastic properties were estimated using the computed Vp, Vs and ? values. Empirical relations between the derived elastic and physical properties of the subsurface lithologies encountered in the boreholes were established. The results show three distinctive layers comprising Sand, Sandy clay and Clayey sand existing in the boreholes. The computed values of the elastic properties show that the formation encountered in the wells are moderately dense and saturated with water. A distinct linear relationship existing between Vp / Vs was observed; while an exponential relationship was derived for ?/Vs. Empirical relationships derived from this study for Vp - Vs is given as Vs = 0.902Vp - 1164, and for Vs - Poisson’s is given as ? = -1E-07Vs2 - 4E-05Vs + 0.502. The values of allowable bearing capacity and the settlement suggest that the study area is able to support engineering construction. Empirical relations established for Vp - Vs and Vs - Poisson’s is characteristics of sedimentary terrain, and can be used within the Escravos area, Niger Delta, Nigeria.

    Keywords: Allowable Bearing Capacity, Elastic Properties, Empirical Relations, Settlement.

  • References

    1. Dobrin MB & Savit CH (1988) Introduction to geophysical prospecting, 4th edn. McGraw-Hill.
    2. Ekweozor CM & Daukoru EM (1994) Northern delta depobelt portion of the Akata- Agbada. (1) Petroleum system, Niger Delta, Nigeria, In, Magom, LB and Dow WG eds. The petroleum system- from source to Trap. Association of American Petroleum Geologists Memoir 60: Tulsa, 599 – 614.
    3. Emujakporue GO & Ekine AS (2009) Determination of rocks elastic constants from compressional and shear waves velocities for Western Niger Delta, Nigeria: Journal of Applied Sciences and Environmental Management Vol. 13(3) 53 – 55.
    4. Gary Mavko (2009) Stanford Rock Physics Laboratory. The rock physics of AVO.
    5. Hardage BA (1985) Vertical Seismic Profiling- part A: Principles, Geophysical Press, London.
    6. Hardage BA (1989) Vertical Seismic Profiling in hydrocarbon exploration and reservoir development. Philips Petroleum Company, Bartlesville, Oklahoma, USA. Circum-Pacific Council for Energy and Mineral Resources 2009 – Petroleum Resources of China and Related Subjects, Vol. 10, 1989.
    7. Hardin BO & Black WL (1968) Vibration modulus of normally consolidated clays, Journal of the Soil Mechanics and Foundation Division, ASCE, Vol.94, No.SM2, pp. 353 - 369.
    8. Imai T & Yoshimura M (1972) the relation of mechanical properties of soils to P and S wave velocities for soil ground in Japan. Urana Research Institute, OYO Corp.
    9. Imai S (1975) an investigation to geophysical prospecting for civil purposes OYO Co-operation, Tokyo, Japan.
    10. Keçeli AD (1990) the determination of the bearing capacity by means of the seismic method: Jeofizik 4, 83 92. (In Turkish).
    11. Keçeli AD (2000) the determination of the presumptive bearing capacity by means of the seismic method: JEOFİZİK, Cilt: 14, Sayı: 1 - 2. (In Turkish).
    12. Keceli AD (2012) Soil parameters that can be determined with seismic velocities. Jeofizik, 2012.
    13. Michele LWT, Ronald RC & Michael E (1999) The Niger delta petroleum system: Niger delta province, Nigeria, Cameroon, and Equatorial Guinea, Africa. Open file report 99 50-H.
    14. Ohkubo T & Terasaki A (1976) Physical property and seismic wave velocity of rocks, OYO Corporation, Japan.
    15. Parry RHG (1977) Estimating bearing capacity of sand from SPT values Journal of Global Environment Engineering, ASCE 103:Gt.9 pp.1014 - 1043.
    16. Sheriff RE (1989) Geophysical methods. Prentice Hall, New Jersey. 1st Edition.
    17. Sternberg BK, Poulton MM & Thomas SJ (1990) Geophysical investigations in support of the Arizona SSC project. (In Geotechnical and Enviromental Geophysics, S.E.G. V.III:211 228).
    18. Uko ED (1996) Thermal modeling of the Northern Niger delta. Unpublished Ph.D. Thesis, Rivers State University of Science and Technology, Port Harcourt.

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  • How to Cite

    Ajayi, T., Adepelumi, A., & Agih, C. (2014). Determination of rock elastic parameters using VP/VS relation-ship for escravos area, Niger delta, Nigeria. International Journal of Advanced Geosciences, 2(2), 140-149. https://doi.org/10.14419/ijag.v2i2.3490

    Received date: 2014-08-31

    Accepted date: 2014-09-22

    Published date: 2014-11-03