The effect of porosity on the seismic waves velocities and elastic coefficients in a South-Western Iran''''s oil field

Document Type : Research Paper


1 Geophysics Research Group, Geoscience Division, Research Institute of Petroleum Industry IRPI, Iran

2 Department of Mining Exploration Engineering, Urmia University, Iran



< p>Petrophysical and geophysical laboratory measurements were performed on ⁽40⁾ samples made of sandstone and limestone in an Oil Field. Parameters including porosity, density and permeability were measured along with the of compressional and shear waves’ velocities of the samples under reservoir conditions. Also, the study of microscopic thin sections, factors affecting the velocity of waves including porosity, Poisson’s ratio, density, pressure and pore type were investigated. The scattering of points in the velocity diagrams of elastic waves based on the petrophysical parameters of the rock indicates that the most important factor of velocity changes is the pore type in the samples in the same porosity value. So, ‹LMR› parameters were calculated using laboratory results of velocity measurement. The values of ‹LMR› parameters of seismic data were determined by the velocities of compressional and shear waves in the pre-stack stage seismic. Then, using seismic inversion, compressional and shear wave resistances were estimated and seismic sections with ‹λ.μ› and ‹μ.ρ› parameters were created. The results show that there is a good correlation between laboratory measurement of rock physics and pre-stack seismic data. Also, the factor affecting the velocity of waves, i.e., the pore types, should also be considered. Uncertainty in velocity values due to the diversity of pores can show differences in the velocity of elastic waves in the same porosity value to about ⁽1500⁾ m/s. Also, at a constant velocity, porosity changes of up to ⁽20⁾ percent are visible.


  1. Avseth P, Veggeland T (2015) Seismic screening of rock stiffness and fluid softening using rock-physics attributes, Exploration Geophysicists and American Association of Petroleum Geologists, 3, 4: 85-93. ##
  2. Wyllie M R J, Gregory A R, Gardner LW (1956) Elastic wave velocities in heterogeneous and porous media, Geophysics, 21: 41-70. ##
  3. Pickett G R (1963) Acoustic character logs and their application in formation evaluation, Trans, AIME, 15: 659-667. ##
  4. Raiga-Clemenceau J, Martin J P, Nicoletis S (1986) The concept of acoustic formation factor for more accurate porosity determination from sonic transit time data, The SPWLA 27th Annual Logging Symposium, Houston, Texas. ##
  5. Walsh J (1965) The effect of cracks on the compressibility of rocks, Journal of Geophysical Research, 70: 381-389. ##
  6. Anselmetti F S, Eberli G P (1993) Controls on sonic velocity in carbonate rocks, Pure and Applied Geophysics, 141: 287- 323. ##
  7. Eshelby J D (1957) The determination of the elastic field of an ellipsoidal inclusion and related problems, Proceedings of Royal Society London, 241: 376-396. ##
  8. Hill R (1965) A self-consistent mechanics of composite materials, Journal of the Mechanics and Physics of Solids, 13: 213-222. ##
  9. Kuster G T, Toksöz M N (1974) Velocity and attenuation of seismic waves in two-phase media, Part 1, Theoretical formulations, Geophysics, 39: 587-606. ##
  10. Watt J P, Davies G F, O’Connell R J (1976) The elastic properties of composite materials, Reviews of Geophysics, Space Phys, 14, 541-563. ##
  11. Marion D, Zinszner B (1991) Core analysis to calibrate geophysical interpretation, in Proceeding, 2nd Society of Core Analysis Symposium, 17-34. ##
  12. Anselmetti F S, Eberli G P (1999) The velocity-deviation log: A tool to predict pore type and permeability trends in carbonate drill holes from sonic and porosity or density logs, AAPG Bulletin, 83, 3: 450-466. ##
  13. Marion D, Jizba D (1996) Sonic velocity in carbonate sediments and rocks, In Palaz, I., and Marfurt, K. J., Ed., Carbonate Seismology, SEG Geophysical Developments Series, 6: 75-93. ##
  14. Narongsirikul S, Haque Mondoland N, Jahren J (2019) Acoustic and petrophysical properties of mechanically compacted over consolidated sands: Part 1 – Experimental results, Geophysical Prospecting, 67, 4: 804-824. ##
  15. Yin H (1992) Acoustic velocity and attenuation of rocks: Isotropy, intrinsic anisotropy and stress induced anisotropy. Ph.D. Thesis, Stanford University, CA, United States. ##
  16. Zimmer M A (2003) Seismic velocities of unconsolidated sands: Measurements of pressure, sorting, and compaction effects, Ph.D. Dissertation, Stanford University. ##
  17. Fawad M, Mondol N H, Jahren J, Bjørlykke K (2011) Mechanical compaction and ultrasonic velocity of sands with different texture and mineralogical composition, Geophysical Prospecting, 59, 4: 697- 720. ##
  18. Zadeh M K, Mondol N H, Jahren J (2016) Experimental mechanical compaction of sands and sand–clay mixtures: a study to investigate evolution of rock properties with full control on mineralogy and rock texture, Geophysical Prospecting, 64: 915–941. ##
  19. Smith G C, Gidlow P M (1987) Weighted stacking for rock property estimation and detection of gas, Geophysical Prospecting, 35: 993–1014. ##
  20. Wang Z, Nur A (2000) The Gassmann equation revisited comparing laboratory data with Gassmann prediction, Geophysics Reprint Series, 3: 8-23. ##
  21. Savic M, VerWest B, Masters A, Sena A, Gingrich D (2000) Elastic impedance inversion in practice, 70th Annual International Meeting and Society of Exploration and Geophysics, 689-692. ##
  22. Goodway W, Chen T, Downton J (1997) Improved AVO fluid detection and lithology discrimination using Lame petrophysical parameters; λ.ρ, μ.ρ and λ/μ fluid stack from P and S inversions, 67th Annual International Meeting, SEG, Expanded Abstracts, 183-186. ##
  23. White J E (1983) Underground sound: Application of Seismic wave. Elsevier, New York. ##
  24. Gardner G H F, Gardner LW, Gregory A R (1974) Formation velocity and density, the diagnostic basics for stratigraphic traps, Geophysics, 39: 770-780. ##
  25. Eyinla D S, Oladunjoye M A, Olayinka A I, Bate B B (2021) Rock physics and geo-mechanical application in the interpretation of rock property trends for overpressure detection, Journal of Petroleum Exploration and Production Technology, 11: 75–95. ##
  26. Vernik L, Milovac J (2011) Rock physics of organic shales: The Leading Edge, 30: 318–323. ##
  27. Carcione J, Avseth P (2015) Rock physics templates for clay-rich source rocks: Geophysics, 80, 5. ##
  28. Close D, Perez M (2015) Unconventional resource evaluation and applied geophysics utilizing LMR, 24th International Geophysical Conference and Exhibition, ASEG-PESA, Expanded Abstracts, D2. ##
  29. Avseth P, Jørstad A, Van Wijngaarden A J, Mavko G (2009) Rock physics estimation of cement volume, sorting, and net-to-gross in North Sea sandstones, The Leading Edge, 28: 98–108. ##
  30. Avseth P, Mukerji T, Mavko G, Dvorkin J (2010) Rock physics diagnostics of depositional texture, diagenetic alterations, and reservoir heterogeneity in high-porosity siliciclastic sediments and rocks — A review of selected models and suggested workflows: Geophysics, 75: 5, 31–47. ##
  31. Avseth P, Johansen T A, Bakhorji A, Mustafa H M (2014) Rock-physics modelling guided by depositional and burial history in low-to-intermediate-porosity sandstones, Geophysics, 79, 2: 115–121. ##
  33. Domenico S N (1984) Rock lithology and porosity determination from shear and compressional wave velocity Geophysics, 49, 8: 1188-1195. ##