Seismic Velocity Analysis for Improved Geopressure Modelling in Onshore Niger Delta

  • Authors

    • Emmanuel Bassey Umoren University of Uyo, Nigeria
    • Etim Daniel Uko
    • Iyeneomie Tamunobereton-Ari
    • Chigozie Israel-Cookey
    2019-12-15
    https://doi.org/10.14419/ijag.v7i2.29958
  • Niger Delta, Geopressure, Seismic Inversion, Acoustic Impedance, Seismic Velocities.

  • Abstract

    In this study, an improved evaluation of pore pressure using a model based seismic inversion technique has been carried out. Across six wells in the Onshore Niger Delta Basin, post stack seismic volume, angle stack gathers, seismic horizons, check shot, wireline logs, drilling and pressure data were analysed and interpreted. The model based inversion technique was applied to improve the seismic resolution as well as derive acoustic impedance using well velocities along with stacking velocities from velocity analysis of the 3D seismic data. Bowers’ Vp-VES coefficients of 7.43 and 0.77 were used to transform the derived seismic acoustic impedance velocity into seismic pore pressure cube. The seismic acoustic impedance interval velocity reveals much of the geology and resulted to a high resolution seismic pore pressure cube when compared at well location with direct pressure data. The Derived Seismic Pore Pressure (DSPP) also revealed that pore pressure and overpressure can reach or exceed 4000 and 1000psi respectively in the field. The results obtained have demonstrated that seismic acoustic impedance volume can offer high resolution seismic pore pressure cube in both time and space.

     

     

  • References

    1. [1] Bowers, G. L. (2001). Determining an appropriate pore pressure estimation strategy, Offshore Technology Conference, Paper OTC 13042. https://doi.org/10.4043/13042-MS.

      [2] Bowers, G. L. (2002). Detecting high Overpressure. The Leading Edge, 174-177. https://doi.org/10.1190/1.1452608.

      [3] Dix, C. H. (1955). Seismic velocities from surface measurements. Geophysics, 20, 68-66. https://doi.org/10.1190/1.1438126.

      [4] Doust, H. & Omatsola, E. (1990). Niger Delta. In Edwards, J. D. and Santogross, P. A., Divergent / Passive margin Basins. AAPG Memoir. American Association of Petroleum Geologists, Tulsa, OK, 48, 239-248.

      [5] Dutta, N. C. (2002). Geopressure prediction using seismic data: Current status and the road ahead. Geophysics, 67 (6), 2012-2041. https://doi.org/10.1190/1.1527101.

      [6] Hooper, R. J., Fitzsimmons, R. J., Grant, N and Vendeville, B. C. (2001). The role of deformation in controlling depositional patterns in the South-Central Niger Delta, West Africa. Journal of Structural Geology, 24, 847 – 859. https://doi.org/10.1016/S0191-8141(01)00122-5.

      [7] Jones, P. H. (1978). Problems of migration. American Association of Petroleum Geologists Bulletin, 10, 207 – 216.

      [8] Kulke, H. (1995). Nigeria. In Kulke, H., ed., Regional Petroleum Geology of the World. Part II: Africa, America, Australia and Artarctica: Berlin, GebruderBorntraeger, 143-172.

      [9] Opara, A. I. (2010). Prospectivity Evaluation of Usso Field, Onshore Niger Delta Basin, using 3-D Seismic and Well Log Data. Petroleum and Coal, 52(4), 308-313.

      [10] Opara, A. I., Anyiam, U. O. and Nduka, A. V. (2011). 3-D Seismic Interpretation and Structural Analysis of Ossu Oilfield, Northern Depobelt, Onshore Niger Delta, Nigeria. The Pacific Journal of Science and Technology, 12 (1), 502-508.

      [11] Osionowo, O. O., Oladunjoye, M. A. and Olayinka, A. I. Overpressure prediction from seismic data: implication for drilling safety. American Geophysical Union, Fall Meeting 2007, Abstract S23A – 1113.

      [12] Owolabi, O. O., Okpobiri, G. A. and Obomanu, I. A. (1990). Prediction of abnormal pressure in the Niger Delta using well logs. CIM/SPE International Technical Meeting, Calgary, Canada. https://doi.org/10.2118/21575-MS.

      [13] Pennebaker, E. S. (1968). Seismic data indicate depth and magnitude of abnormal pressure. World Oil, 166, 73-82.

      [14] Reijers, T. J. A., Petters, S. W. & Nwajide, C. S. (1997). The Niger Delta Basin. In Selley, R. C., ed., African Basins: Sedimentary Basins of the World. Elservier, 3, 143-172. https://doi.org/10.1016/S1874-5997(97)80010-X.

      [15] Sayers, C. M., Woodward, M. J., Bartman, R. C. (2002). Seismic pore-pressure prediction using reflection tomography and 4-C seismic data. The Leading Edge, 21(2), 188-192. https://doi.org/10.1190/1.1452611.

      [16] Connolly, P. (1999). Elastic impedance. The Leading Edge, April, 438-452. https://doi.org/10.1190/1.1438307.

      [17] Udo, K.I, Akpan, M.J and Agbasi,O. E.(2015). Estimation of Overpressures in Onshore Niger Delta Using Wire-line Data. International Journal of Science and Research, 4 (5), 2780-2784.

      [18] Ugwu, G. Z. (2015). An overview of pore pressure using seismically-derived velocities. Journal of Geology and Mining Research, 7(4), 31-40. https://doi.org/10.5897/JGMR15.0218.

      [19] Uko, Etim D., Emudianughe, Juliet E. and Tamunobereton-ari, I. (2013). Overpressure Prediction in the North-West Niger Delta, using Porosity Data. IOSR Journal of Applied Geology and Geophysics, 1(3), 42-50. https://doi.org/10.9790/0990-0134250.

      [20] Zhang, J. (2011). Pore pressure prediction from well logs, modification and new approaches. Earth Science Review, 108, 50-63. https://doi.org/10.1016/j.earscirev.2011.06.001.

  • Downloads

  • How to Cite

    Bassey Umoren, E., Daniel Uko, E., Tamunobereton-Ari, I., & Israel-Cookey, C. (2019). Seismic Velocity Analysis for Improved Geopressure Modelling in Onshore Niger Delta. International Journal of Advanced Geosciences, 7(2), 179-185. https://doi.org/10.14419/ijag.v7i2.29958

    Received date: 2019-10-10

    Accepted date: 2019-11-06

    Published date: 2019-12-15