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A Comparative Model Approach to Pore Pressure Prediction Applied to Central/Coastal Swamp Depobelt of the Niger Delta Basin
Authors(2) :-Mkpese Ubon Udofia, Ekine Anthony Sotonye
Overpressured zones and porosity values in shale beds have been estimated for selected fields of the central/coastal swamp depo-belts of the Niger Delta. Pore pressure prediction (PPP), when done accurately can be used to avert disaster and helps in safe drilling. Eaton’s sonic model, Bowers’ model and Zhang’s porosity-based model have been applied to predict overpressures using petrophysical log data from six 6 wells, each representing a field of the studied area. Predicted zones of hard overpressures (HOVP > 0.70 psi/ft) are generally below the depth of 10000ft. Top of geopressures (TOG) for the case study wells; WELL_A, WELL_B, WELL_D, WELL_G, WELL_H and WELL_K are 7000ft, 10500ft, 10000ft, 12500ft, 9000ft and 10400ft respectively. Eaton exponent ‘5.5’ and Bowers model plotted with robust matches to measured pore pressures (MPP) everywhere except in one well. The porosity model equally yielded better matches to MPPs with higher values of fluid-transit-times typical of hydrocarbon fluid type (oil). These suggest, in combination with Vp-density analyses, a strong evidence of secondary mechanism causing overpressure in the basin. Very hard overpressures characterizes the deeper section of the basin (lower part of Agbada formation) at most of the well locations suggesting a strong evidence of fluid expansion mechanism which is also related to sediments unloading. The robust concordance between PPP and MPP profiles validates the results here and is a better guide for future drilling.
Mkpese Ubon Udofia, Ekine Anthony Sotonye
Eaton's Model, Pore Pressure Prediction, Disequilibrium Compaction, Niger Delta, Porosity Model, Overpressure Mechanism, Unloading Mechanism.
- Anowai, C.A., Ejedawe, J.E., and Adeoye, S.S. (2003); Regional Overpressure Study of the Niger Delta using seismic velocities. EP2003 ? 5382.
- Bowers, G. L., (1995); Pore Pressure Estimation from Velocity Data: Accounting for Overpressure Mechanisms Besides Undercompaction: SPE Drilling and Completions, June, 1?19.
- Carmichael, R. S., (1982); Handbook of Physical Properties of Rocks. CRC Press Inc. Boca Rahn, Florida. Vol. 2, 1-228.
- 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, 239-248.
- Eaton, B. A., (1975); The Equation for Geopressure Prediction from Well Logs. Society of Petroleum? Engineers of AIME, paper SPE 5544.
- Flemings, P.B., Stump B.B., Finkbeiner, T. and Zoback, M. (2002); Flow focusing in overpressured sandstones: theory, observations, and applications. American J. of Science, Vol. 302, 827?855.
- Holbrook, P.W., Maggiori, D.A., and Hensley, R., (2005); Real-time Pore Pressure and Fracture Gradient Evaluation in all Sedimentary Lithologies. SPE Formation Evaluation, Vol. 10, No. 5, 215-222.
- Kumar, B., Niwas, S. and Mangaraj, B.K. (2012);Pore Pressure Prediction from Well Logs and Seismic Data. 9th Biennial Intl Conf & Exposition on Pet. Geophy.
- Lambert-Aikhionbare, D. O. and Shaw, H. F. (1982); Significance of Clays in the Petroleum Geology of the Niger Delta. Clay minerals, Vol. 17, 91-103.
- Nwozor, K. M., Omudu, M.L., Ozumba, B.M., Egbuachor, C.J., Onwuemesi, A.G. and Anike, O.L. (2013); Quantitative Evidence of Secondary Mechanisms of Overpressure Generation: Insights from Parts of Onshore Niger Delta, Nigeria. Petroleum Technology Development Journal, Vol. 3, No. 1, 64-83
- O’Connor, S., Swarbrick, R., Hoesni, J. and Lahann, R., (2011); Deep Pore Pressure Prediction in Challenging areas, Malay Basin, SE Asia. Proceedings, Indonesia Petroleum Association. IPA11- G-022.?
- Opara, A. I., (2011); Estimation of Multiple Sources of Overpressures Using Vertical Effective Stress Approach: Case Study of the Niger Delta, Nigeria. Petroleum & Coal, Vol. 53, No. 4, 302-314.
- Osborne, M.J., and Swarbrick, R.E., (1997) Mechanisms for Generating Overpressure in Sedimentary Basins: A Reevaluation: AAPG Bulletin, Vol. 81, 1023-1041.
- Short, K.C. & Stauble, A.J., (1967); Outline geology of the Niger Delta. American Association of Petroleum Geologists Bulletin, Vol. 5, 761?779.
- Swarbrick, R. E. and Osborne, M.J. (1998); Mechanisms which Generate Overpressure in Sedimentary Basins: a reevaluation. AAPG Bulletin, Vol. 81, 1023-1041.
- Traugott, M., (1997); Pore pressure and fracture gradient determinations in deepwater. World Oil, August, 815.
- Tuttle, M., Charpentier, R., and Brownfield, M. (2015); The Niger Delta Petroleum System: Niger Delta Province, Nigeria, Cameroon, and Equatorial Guinea, Africa. United States Geologic Survey.
- Ugwu, G.Z. (2015); An Overview of Pore Pressure Prediction Using Seismically?Derived Velocities. Journal of Geology and Mining Research, Vol. 7, No. 4, 31-40.
- Zhang, J. (2011); Pore Pressure Prediction from Well Logs: Methods, Modifications, and New Approaches. Earth-science Reviews, Vol. 108, 50-63.
Published in : Volume 3 | Issue 8 | November-December 2017
Date of Publication : 2017-12-31
License: This work is licensed under a Creative Commons Attribution 4.0 International License.
Page(s) : 359-368
Manuscript Number : IJSRST173813
Publisher : Technoscience Academy
PRINT ISSN : 2395-6011
ONLINE ISSN : 2395-602X
Cite This Article :
Mkpese Ubon Udofia, Ekine Anthony Sotonye, "A Comparative Model Approach to Pore Pressure Prediction Applied to Central/Coastal Swamp Depobelt of the Niger Delta Basin", International Journal of Scientific Research in Science and Technology(IJSRST), Print ISSN : 2395-6011, Online ISSN : 2395-602X, Volume 3, Issue 8, pp.359-368, November-December-2017
URL : http://ijsrst.com/IJSRST173813