1887

Abstract

Summary

A multi-frequency band elastic parameters measurement system was used to measure the dispersive nature of elastic waves in a tight sandstone under nitrogen gas and glycerin saturation. The measurements were performed at effective pressure Peff = [2–35] MPa and at temperature 23°C, 40°C and 60 °C. For nitrogen gas saturated (dry) rock, velocities remained almost unchanged from low seismic to high ultrasonic frequencies at each effective pressure. But under glycerin saturation, the saturated tight sandstone exhibited obvious velocity variations in the seismic frequency region, which were largely damped by the increase in effective pressure. Furthermore, an increase in fluid viscosity caused a shift of the dispersion curve to lower frequencies, suggesting a fluid flow mechanism where the characteristic frequency was inversely proportional to fluid viscosity. A simple squirt flow model was used to estimate the frequency effect and fitted the behavior observed in our dataset relatively well. Although the magnitude of velocities in measurement and estimation did not match exactly, the characteristic frequency changed with viscosity and effective pressure as predicted by the squirt flow theory. So for the “crack-pore” tight sandstone, it is the squirt flow mechanism that causes the dispersion phenomenon in the seismic frequency band.

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/content/papers/10.3997/2214-4609.201701104
2017-06-12
2020-04-05
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References

  1. Batzle, M. L., Han, D. H. and Hofmann, R.
    [2006] Fluid mobility and frequency-dependent seismic velocity - Direct measurements. Geophysics, 71(1), N1–N9.
    [Google Scholar]
  2. Gurevich, B., Makarynska, D., de Paula, O. B. and Pervukhina, M.
    [2010] A simple model for squirt-flow dispersion and attenuation in fluid-saturated granular rocks. Geophysics, 75(6), N109–N120.
    [Google Scholar]
  3. Müller, T. M., Gurevich, B. and Lebedev, M.
    [2010] Seismic wave attenuation and dispersion resulting from wave-induced flow in porous rocks—A review. Geophysics, 75(5), 75A147–75A164.
    [Google Scholar]
  4. Pervukhina, M., Gurevich, B., Dewhurst, D. N. and Siggins, A. F.
    [2010] Applicability of velocity— stress relationships based on the dual porosity concept to isotropic porous rocks. Geophysical Journal International, 181(3), 1473–1479.
    [Google Scholar]
  5. Pimienta, L., Fortin, J. and Guéguen, Y.
    [2015] Experimental study of Young’s modulus dispersion and attenuation in fully saturated sandstones. Geophysics, 80(5), L57–L72.
    [Google Scholar]
  6. Spencer, J. W.
    [1981] Stress relaxations at low frequencies in fluid-saturated rocks: Attenuation and modulus dispersion. Journal of Geophysical Research: Solid Earth, 86, 1803–1812.
    [Google Scholar]
  7. Yin, H., Wang, S., Zhao, J., Ma, X., Zhao, L. and Cui, Y.
    [2016] A laboratory study of dispersion and pressure effects in partially saturated tight sandstone at seismic frequencies. 86th Annual SEG Meeting, Expanded Abstracts, 3236–3240.
    [Google Scholar]
  8. Zhao, Z. J., Wang, W. S., Li, L., Wei, W. and Yin, Y.
    [2014] Studies on Dispersion of Reservoir Rocks Using Multi-band Direct Laboratory Measurement Methodology With μ-CT Scanning. 76th EAGE Conference & Exhibition, Extended Abstracts.
    [Google Scholar]
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