Porosity Prediction for Some Geological intervals in the East Baghdad Oil Field Using New Empirical Equations

Year 2021, Volume: 64 Issue: 2, 223 - 232, 07.04.2021

Maan Abdullah

https://doi.org/10.25288/tjb.766968

Abstract

This study examines the evaluation of empirical equations related to primary seismic velocity with density and porosity. The empirical equations have been used in 128 sites based on a seismic grid covering the east Baghdad oil field. The average of density of the geological formations between each seismic reflectors and another (each interval) was extracted from well log data for four wells scattered in the field. Those reflectors were arranged from top to bottom of the studied Formations (Fatha, Hartha, Tanuma, Ahmadi, Shuaiba, and Gutnia Formations). In order to determine the best empirical equations, several previous equations were tested to obtain the best that correspond to the density rates taken from well records. The most suitable equations were used in calculating density for all intervals in the whole field. Using the strong relationship (porosity-density) taken from the well log data, the porosity values for all the studied intervals were found. Later, the porosity and density contour maps for each interval in the whole field were established. The locations of high porosity zones were identified and related to the petroleum distribution in the field.

Keywords

Density , East Baghdad oil field , petrophysical parameters , porosity , new empirical equations , seismic velocity analyses

References

• Al-Ameri, T.K. (2011). Khasib and Tannuma oil sources, East Baghdad oil field, Iraq. Marine and Petroleum Geology, 28(4), 880-894. https://doi.org/10.1016/j.marpetgeo.2010.06.003
• Al-Ameri, T. K., Al-Temimi A. K. & Zumberge J. (2016). Assessments of oil characterization, source affinities, and hydrocarbon dynamic of East Baghdad oil fields, Central Iraq. Marine and Petroleum Geology, 77, 353-375. https://doi.org/10.1016/j.marpetgeo.2016.03.009
• Al-majid, M. (1992). The study of compaction in the east Baghdad oil field by using seismic velocity analyses (Unpublished MSc thesis). University of Mosul, Iraq.
• Barnola, A. S. & White, R. E. (2001). Gardner’s relation and AVO inversion. First Break, 19(11), 607-611.
• Brocher, T. M. (2005). Empirical relations between elastic wave speeds and density in the Earth’s crust. Bulletin of the Seismological Society of America, 95(6), 2081–2092.
• C.F.P. (Compagnie FranGaise du Pdtrole) (1981). East Baghdad field: sedimentological study of the carbonate reservoirs. Oil Exploration Co., Baghdad [Unpublished report,].
• Darweesh, H. A., Obed, A. M. & Albadran, B. N. (2017). Structural study of East- Baghdad oil field, Central-Iraq. World Journal of Engineering Research and Technology, 3(6), 56 -66.
• Gardner, G. H. F., Gardner, L. W. & Gregory, A. R. (1974). Formation velocity and density – the diagnostic basics for stratigraphic traps. Geophysics, 39, 770-780.
• Han, D. H., Nur, A. & Morgan, D. (1986). Effects of porosity and clay content on wave velocities in sandstones. Geophysics, 51, 2093-2107.
• Han, D. H. & Batzle, M. (2004). Gassmann’s equation and fluid-saturation effects on seismic velocities. Geophysics, 69, 398–405.
• Harding, T. P. & Lowell, J. D. (1979). Structural styles, their plate-tectonic habitats, and hydrocarbon traps in petroleum province. The American Association of Petroleum Geologists Bulletin, 63(7),1016-1058.
• Khaiwka, M. H. (1989). Structural evolution of the East Baghdad oilfield, central Iraq. Proc. 5th Sci. Con., Scientific Research Council, Baghdad, 2,(l), 17-27.
• Kuiper, J., Van Ryan, W. M. L. & Kocfoed, O. (1959). Laboratory determinations of elastic properties of some limestones. Geophysical Prospecting, 7(1), 38-14. Lindseth, R. O. (1979). Synthetic sonic logs - a process for stratigraphic interpretation. Geophysics, 44, 3-26.
• Nwozor, K. K., Onuorah, L. O., Onyekuru, S.O. & Egbuachor, C. J. (2017). Calibration of Gardner coefficient for density–velocity relationships of tertiary sediments in Niger Delta Basin. Journal of Petroleum Exploration and Production Technology, 7, 627–635. https://doi.org/10.1007/s13202-017-0313-7
• Van Koughnet, R. W., Skidmore, C. M., Kelly, M. C. & Lindsay, R. (2003). Prospecting with the density cube. The Leading Edge, 22, 1038-1045.