1887
Volume 42, Issue 1
  • ISSN: 0812-3985
  • E-ISSN: 1834-7533

Abstract

For effective and accurate prediction of overpressure in the Efomeh field, located in the Niger delta basin of Nigeria, integrated seismic and borehole analyses were undertaken. Normal and abnormal pore pressure zones were delineated based on the principle of normal and deviation from normal velocity trends. The transition between the two trends signifies the top of overpressure. The overpressure tops were picked at regular intervals from seismic data using interval velocities obtained by applying Dix’s approximation. The accuracy of the predicted overpressure zone was confirmed from the sonic velocity data of the Efomeh 01 well. The variation to the depth of overpressure between the predicted and observed values was less than 10 m at the Efomeh 01 well location, with confidence of over 99 per cent. The depth map generated shows that the depth distribution to the top of the overpressure zone of the Efomeh field falls within the sub-sea depth range of 2655 ± 2 m (2550 ms) to 3720 ± 2 m (2900 ms). This depth conforms to thick marine shales using the Efomeh 01 composite log. The lower part of the Agbada Formation within the Efomeh field is overpressured and the depth of the top of the overpressure does not follow any time-stratigraphic boundary across the field. Prediction of the top of the overpressure zone within the Efomeh field for potential wells that will total depth beyond 2440 m sub-sea is very important for safer drilling practice as well as the prevention of lost circulation.

ASEG
Loading

Article metrics loading...

/content/journals/10.1071/EG09040
2011-03-01
2026-01-18

  • From This Site

    /content/journals/10.1071/EG09040
    dcterms_title,dcterms_subject,pub_keyword
    -contentType:Journal -contentType:Contributor -contentType:Concept -contentType:Institution
    10
    5
Loading full text...

Full text loading...

References

  1. Barker C. 1972 Aqua thermal pressuring, role of temperature in development of abnormal pressure zones: AAPG Bulletin 56 2068 2071
    [Google Scholar]
  2. Barker C. 1990 Calculated volume and pressure changes during the thermal cracking of oil to gas in reservoirs: AAPG Bulletin 74 1254 1261
    [Google Scholar]
  3. Bowers, G. L., 1995, Pore-pressure estimation from velocity data: accounting for pore-pressure mechanisms besides undercompaction: SPE Drilling and Completion, 10, 89–95.
  4. Bowers G. L. 2002 Detecting high overpressure: The Leading Edge 21 174 177 10.1190/1.1452608
    https://doi.org/10.1190/1.1452608 [Google Scholar]
  5. Bruce B. 2002 An introduction to this special section ‘pore pressure’: The Leading Edge 21 169 177 10.1190/1.1452606
    https://doi.org/10.1190/1.1452606 [Google Scholar]
  6. Dix C. H. 1955 Seismic velocities from surface measurements: Geophysics 20 68 86 10.1190/1.1438126
    https://doi.org/10.1190/1.1438126 [Google Scholar]
  7. Dutta N. C. 1997 Pressure prediction from seismic data: NPF Special Publication 7 187 199 10.1016/S0928‑8937(97)80016‑1
    https://doi.org/10.1016/S0928-8937(97)80016-1 [Google Scholar]
  8. Dutta N. C. 2002 a Deepwater geoharzard prediction using prestack inversion of large offset p – wave data and rock model: AAPG Bulletin 21 193 198
    [Google Scholar]
  9. Dutta N. C. 2002 b Geopressure prediction using seismic data: Current status and the road ahead: Geophysics 67 2012 2041 10.1190/1.1527101
    https://doi.org/10.1190/1.1527101 [Google Scholar]
  10. Fertl, W. H., 1976, Abnormal formation pressures, Developments in Petroleum Science No. 2: Elsevier.
  11. Gardner G. H. F. Gardner L. W. Gregory A. R. 1974 Formation velocity and density the diagnostic bases of stratigraphic trap: Geophysics 39 770 780 10.1190/1.1440465
    https://doi.org/10.1190/1.1440465 [Google Scholar]
  12. LaPorte, N., 2010, A Gulf coast Fisherman’s survival story: The Daily Beast Online News June 1, 2010 . Available online at: http://www.thedailybeast.com/blogs-and-stories/2010-06-01/life-gets-worse-on-the-gulf-coast/?cid=tag:all5 [verified January 2011].
  13. Martinsen R. S., 1994, Summary of published literature on anomalous pressures: implications for the study of pressure, in P. J. Ortoleva, ed., Basin Compartments and Seals. AAPG, Memoir 61, Tulsa, OK, pp. 27–36.
  14. Mouchet, J. P., and Mitchell, A., 1989, Abnormal pressure while drilling. Elf Aquitaine Manuals Techniques 2: Boussens, France.
  15. Mufson, S., 2010, Gulf of Mexico oil spill creates environmental and political dilemmas: Washington Post, April 27, 2010. Available online at: www.washingtonpost.com/wp-dyn/content/article/2010/04/26/AR2010042604308.html [verified January 2011].
  16. Osborne M. J. Swarbrick R. E. 1997 Mechanism for generating overpressure in sedimentary basins: A re-valuation: AAPG Bulletin 81 1023 1041
    [Google Scholar]
  17. Osinowo, O.O., Oladunjoye, M.A. and Olayinka, A.I., 2007, Overpressure prediction from seismic data: implications on drilling safety: 40th American Geophysical Union, fall meeting 2007, San Francisco, USA
  18. Pennebaker, E. S., 1968, Seismic data indicate depth, magnitude of abnormal pressure: WorldOil, 166, 73–77.
  19. Pickett G. R. 1963 Acoustic character logs and their application in formation evaluation: Journal of Petroleum Technology 15 659 667 10.2118/452‑PA
    https://doi.org/10.2118/452-PA [Google Scholar]
  20. Reijers, T. J. A., Petters, S. W., and Nwajide, C. S., 1997, The Niger delta basin. African Basins, in R. C. Selley, ed., Sedimentary Basins of the World 3: Elsevier, pp. 151–172.
  21. Rubey W. W. Hubbert M. K. 1959 Role of fluid pressure in mechanics of overthrust faulting: AAPG Bulletin 70 167 206
    [Google Scholar]
  22. Sayers C. M. Den Boer L. D. Nagy Z. R. Hooyman P. J. 2006 Well-constrained seismic estimation of pore pressure with uncertainty: The Leading Edge 25 1524 1526 10.1190/1.2405338
    https://doi.org/10.1190/1.2405338 [Google Scholar]
  23. Short K. C. Stauble A. J. 1967 Outline of geology of the Niger Delta: AAPG Bulletin 51 761 779
    [Google Scholar]
  24. Weber, K. J., and Daukoro, E. M., 1975, Petroleum geology of the Niger Delta: Tokyo 9th World Petroleum Congress Proceedings: 2, pp. 209–221.
  25. Wikipedia, 2010, Free Encyclopedia, 20 August 2010.
  26. Wolinsky M. A. Pratson L. F. 2007 Overpressure and slope stability in prograding clinoforms: Implications for marine morphodynamic: Journal of Geophysical Research 112 F04011 10.1029/2007JF000770
    https://doi.org/10.1029/2007JF000770 [Google Scholar]
/content/journals/10.1071/EG09040
Loading
Overpressure prediction of the Efomeh field using synthetic data, onshore Niger Delta, Nigeria
Exploration Geophysics 42, 50 (2011); https://doi.org/10.1071/EG09040
/content/journals/10.1071/EG09040
/content/journals/10.1071/EG09040
Loading

Data & Media loading...

  • Article Type: Research Article
Keyword(s): Efomeh, Niger Delta, overpressure prediction, seismic, synthetic, velocity.

Most Cited This Month Most Cited RSS feed

This is a required field
Please enter a valid email address
Approval was a Success
Invalid data
An Error Occurred
Approval was partially successful, following selected items could not be processed due to error