Seismic wave attenuation in rock due to friction

Walsh, J. B.

doi:10.1029/jz071i010p02591

Cited by 253 publications

(129 citation statements)

References 17 publications

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“…Major factors that play a crucial role are lithology, fluid type, and structural features (Walsh, 1966;Johnston et al, 1979;Toksöz et al, 1979;Winkler et al, 1979;Spencer, 1979;Toksöz and Johnston, 1981;Winkler and Nur, 1982;Murphy et al, 1986;Pointer et al, 2000;Parra et al, 2002;Prasad and Nur, 2003;Behura, 2009). The exact details of the sedimentary environment of the study area are not well known, but it is believed to be composed of smoothly deposited layers of contourite deposits (Eiken and Hinz, 1993;Howe et al, 2008).…”

Section: Discussionmentioning

confidence: 99%

Gas hydrate and free gas detection using seismic quality factor estimates from high-resolution P-cable 3D seismic data

et al. 2016

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We have estimated the seismic attenuation in gas hydrate and free-gas-bearing sediments from high-resolution P-cable 3D seismic data from the Vestnesa Ridge on the Arctic continental margin of Svalbard. P-cable data have a broad bandwidth (20-300 Hz), which is extremely advantageous in estimating seismic attenuation in a medium. The seismic quality factor (Q), the inverse of seismic attenuation, is estimated from the seismic data set using the centroid frequency shift and spectral ratio (SR) methods. The centroid frequency shift method establishes a relationship between the change in the centroid frequency of an amplitude spectrum and the Q value of a medium. The SR method estimates the Q value of a medium by studying the differential decay of different frequencies. The broad bandwidth and short offset characteristics of the P-cable data set are useful to continuously map the Q for different layers throughout the 3D seismic volume. The centroid frequency shift method is found to be relatively more stable than the SR method. Q values estimated using these two methods are in concordance with each other. The Q data document attenuation anomalies in the layers in the gas hydrate stability zone above the bottom-simulating reflection (BSR) and in the free gas zone below. Changes in the attenuation anomalies correlate with small-scale fault systems in the Vestnesa Ridge suggesting a strong structural control on the distribution of free gas and gas hydrates in the region. We argued that high and spatially limited Q anomalies in the layer above the BSR indicate the presence of gas hydrates in marine sediments in this setting. Hence, our workflow to analyze Q using high-resolution P-cable 3D seismic data with a large bandwidth could be a potential technique to detect and directly map the distribution of gas hydrates in marine sediments.

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Section: Discussionmentioning

confidence: 99%

Gas hydrate and free gas detection using seismic quality factor estimates from high-resolution P-cable 3D seismic data

et al. 2016

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“…This claim cannot be correct since it may be shown [Mavko, 1979], that static friction cannot increase the loss. Walsh [1966] The dependence of the wave velocity on frequency is such that it is difficult to separate it from the effects of spatial heterogeneities. There is however an increasing amount of evidence in support of the frequency dependence of the elastic moduli.…”

Section: Discussionmentioning

confidence: 99%

Constant Q‐wave propagation and attenuation

Kjartansson¹

1979

J. Geophys. Res.

983

411

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A linear model for attenuation of waves is presented, with Q, or the portion of energy lost during each cycle or wavelength, exactly independent of frequency. The wave propagation is completely specified by two parameters, e.g., Q and Co, a phase velocity at an arbitrary reference frequency w0. A simple exact derivation leads to an expression for the phase velocity c as a function of frequency: C/Co = (w/w0)*, where 7 = (l/•r) tan -x (l/Q). Scaling relationships for pulse propagation are derived and it is shown that for a material with a given value of Q, the risetime or the width of the pulse is exactly proportional to travel

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“…In this case, the velocity ratio generally trends between the velocity ratio of the mineral grains and the values for a suspended mixture of fluid and minerals. However, in an anisotropic medium the Poisson ratio and the velocity ratio depend on the orientation of wave propagation, crack density, and crack geometry (Walsh, 1966;Mavko et al, 2003). …”

Section: Assumptions and Limitationsmentioning

confidence: 99%

Static and Dynamic Moduli of Malm Carbonate: A Poroelastic Correlation

Hassanzadegan

Guerizec

Reinsch

et al. 2016

Pure Appl. Geophys.

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The static and poroelastic moduli of a porous rock, e.g. the drained bulk modulus, can be derived from stress-strain curves in rock mechanical tests and the dynamic moduli, e.g. dynamic Poisson's ratio, can be determined by acoustic velocity and bulk density measurements. As static and dynamic elastic moduli are different a correlation is often required to populate geomechanical models. A novel poroelastic approach is introduced to correlate static and dynamic bulk moduli of outcrop analogues samples, representative of Upper-Malm reservoir rock in the Molasse basin, southwestern Germany. Drained and unjacketed poroelastic experiments were performed at two different temperature levels (30 and 60• C). For correlating the static and dynamic elastic moduli, a drained acoustic velocity ratio is introduced, corresponding to the drained Poisson's ratio in poroelasticity. The strength of poroelastic coupling, i.e. the product of Biot and Skempton coefficients here, was the key parameter. The value of this parameter decreased with increasing effective pressure by about 56% from 0.51 at 3 MPa to 0.22 at 73 MPa. In contrast, the maximum change in Pand S-wave velocities was only 3% in this pressure range. This correlation approach can be used in characterizing underground reservoirs, and can be employed to relate seismicity and geomechanics (seismo-mechanics).

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Seismic wave attenuation in rock due to friction

Cited by 253 publications

References 17 publications

Gas hydrate and free gas detection using seismic quality factor estimates from high-resolution P-cable 3D seismic data

Gas hydrate and free gas detection using seismic quality factor estimates from high-resolution P-cable 3D seismic data

Constant Q‐wave propagation and attenuation

Static and Dynamic Moduli of Malm Carbonate: A Poroelastic Correlation

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