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REFERENCES

[ht]2mssdvel_big,msszw_big,mssdpatchsy_big,mssdpatchxy_bigwidth=2.88in,height=2.4inVarious methods of plotting 560 Hz Massillon sandstone data of Murphy (1984): (a) Compressional and shear wave velocities as a function of saturation, (b) transform to ($\rho/\lambda$, $\mu/\lambda$)-plane, (c) $\lambda/\mu$ versus saturation, (d) transform to ($\lambda/\mu$, $\rho/\mu$)-plane. All of these behaviors are anticipated by the Gassmann-Domenico relations for homogeneously mixed fluid in the pores.

[ht]2sandstoneszw_big,limestones500kzw_big,drywetall_big,wg10040010003000zw_bigwidth=2.88in,height=2.4in Examples of the correlation of slopes with porosity in the data-sorting plots: (a) three Spirit River (S.R.) sandstone (Knight and Nolen-Hoeksema, 1990) and Massillon and Ft. Union sandstones (Murphy, 1984), (b) five limestones (Cadoret et al., 1998), (c) 11 fused glass-bead samples (Berge et al., 1995), (d) Westerly granite (Nur and Simmons, 1969) at four pressures. The observed trend is that high porosity samples generally have lower slopes than lower porosities on these plots, although there are a few exceptions as discussed in the text. These trends are easily understood since the slopes are determined approximately by the average value of vs2 for each material, which is a decreasing function of porosity $\phi$.

[ht]2eespdpsypatch_big_a,eespdpxypatch_big_b,ebrauvdpsy_big,ebrauvdpxy_big,evlvsy_big,evlvxy_bigwidth=2.4in,height=2.0in Lamé parameter ratio $\lambda/\mu$ plotted versus (a) saturation and (b) $\rho/\mu$ for Espeil limestone, (c) saturation and (d) $\rho/\mu$ for Brauvilliers limestone, and (e) saturation and (f) $\rho/\mu$ for Volvic andesite. All extensional and shear wave measurements (Cadoret, 1993; Cadoret et al., 1995; 1998) were made at 1 kHz. Note that (a) and (b) indicate homogeneous mixing of liquid and gas, (e) and (f) indicate extremely patchy mixing, while (c) and (d) show an intermediate state of mixing for the drainage data, but more homogeneous mixing for the depressurization data. The plots on the right are saturation-proxy plots, having essentially the same behavior as the plots on the left but requiring only velocity data.


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Stanford Exploration Project
4/28/2000