1887
Volume 55, Issue 2
  • E-ISSN: 1365-2478

Abstract

ABSTRACT

The link between the stress sensitivity of shaley sandstones and their porosity and clay content is investigated. This is achieved by firstly fitting a compliance‐based stress‐sensitivity law to laboratory measurements of ultrasonic velocity taken from four sets of reservoir sandstones, extracted from a variety of depositional settings. Correlations are then sought between the independent parameters of this law and the porosity or clay fraction of the rocks, which are then subsequently interpreted in terms of framework or pore‐space‐related microstructural clay models. The general conclusion drawn from the results is that both of the parameters defining the stress‐sensitivity law (the asymptotic modulus and the stress‐dependent excess compliance) clearly vary with porosity. However, only the asymptotic modulus shows a convincing trend with clay and there is little observed variation of the stress‐dependent compliance with clay. There is therefore a resultant variation of stress sensitivity with clay, but it is controlled only by the asymptotic modulus. The analysis also concludes that all four data sets fall into a framework‐related category of clay model.

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2007-02-12
2020-04-03
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References

  1. AnsteyN.A.1991. Velocity in thin section. First Break9, 449–457.
    [Google Scholar]
  2. BryantS. and RaikesS.1995. Prediction of elastic‐wave velocities in sandstones using structural models. Geophysics60, 437–446.
    [Google Scholar]
  3. Eberhart‐PhillipsD., HanD.‐H. and ZobackM.D.1989. Empirical relationships among seismic velocity, effective pressure, porosity, and clay content in sandstone. Geophysics54, 82–89.
    [Google Scholar]
  4. HanD., NurA. and MorganD.1986. Effects of porosity and clay content on wave velocities in sandstones. Geophysics51, 2093–2107.
    [Google Scholar]
  5. HornbyB.E. and MurphyW.F.1987. VP/VS in unconsolidated oil sands: Shear from Stoneley. Geophysics52, 502–513.
    [Google Scholar]
  6. KhaksarA. and GriffithsC.2000. Effects of porosity and clay content on P‐ and S‐wave velocities in Cooper Basin sandstones. Exploration Geophysics31, 433–440.
    [Google Scholar]
  7. KhaksarA., GriffithsC.M. and McCannC.1999. Compressional and shear‐wave velocities as a function of confining stress in dry sandstones. Geophysical Prospecting47, 487–508.
    [Google Scholar]
  8. KlimentosT.1991. The effects of porosity‐permeability‐clay content on the velocity of compressional waves. Geophysics56, 1930–1939.
    [Google Scholar]
  9. MacBethC.2004. A classification for the pressure sensitivity properties of a sandstone rockframe. Geophysics69, 497–510.
    [Google Scholar]
  10. MarionD., NurA., YinH. and HanD.1992. Compressional velocity and porosity in sand‐clay mixtures. Geophysics57, 554–563.
    [Google Scholar]
  11. MavkoG., MukerjiT. and DvorkinJ.1998. The Rock Physics Handbook . Cambridge University Press, ISBN. 0521620686.
    [Google Scholar]
  12. MinearJ.1982. Clay models and acoustic velocities. 57th Annual Technical Conference, AIME, SPE, SE 11031.
  13. NurA., MavkoG., DvorkinJ. and GalD.1995. Critical porosity: the key to relating physical properties to porosity in rocks. 65th SEG Meeting, Houston , USA , Expanded Abstracts, 878–881.
  14. SamsM. and AndreaM.2001. The effect of clay distribution on the elastic properties of sandstones. Geophysical Prospecting49, 128–150.
    [Google Scholar]
  15. SayersC.M. and KachanovM.1995. Microcrack‐induced elastic wave anisotropy of brittle rocks. Journal of Geophysical Research100 (B3), 4149–4156.
    [Google Scholar]
  16. SelleyR.C.1982. An Introduction to Sedimentology , 2nd edn. Academic Press, Inc. ISBN 0126363609.
    [Google Scholar]
  17. TosayaC. and NurA.1982. Effects of diagenesis and clays on compressional velocities in rocks. Geophysical Research Letters9, 5–8.
    [Google Scholar]
  18. VanorioT., PrasadM. and NurA.2003. Elastic properties of dry clay mineral aggregates, suspensions and sandstones. Geophysical Journal International155, 319–326.
    [Google Scholar]
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