Ultrasonic <i>P</i> and <i>S</i> wave attenuation in dry and saturated rocks under pressure

Johnston, David H.; Toksöz, M. Nafi

doi:10.1029/jb085ib02p00925

Cited by 172 publications

(91 citation statements)

References 39 publications

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“…Since no core taken in a vertical direction is currently available, this conclusion has not been confirmed experimentally. In due course the digitized waveforms will be subjected to FFT's and Q-values calculated for the rock samples by a spectral ratio's technique such as that described by Johnston and Toksoz (1980). The velocity and frequency data correspond to a model of a jointed rock mass in which the joints intersected in the vertical direction are fewer and probably tighter than those intersected in the horizontal direction.…”

Section: Methodsmentioning

confidence: 99%

Cross-hole acoustic measurements in basalt

Myer

Rezowalli

1986

International Journal of Rock Mechanics and Mining Sciences &am

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A series of cross-hole acoustic measurements have been performed in a columnar-jointed basaltic rock mass around an underground opening mined by the drill-and-blast method. The purposes of the test program were: to evaluate the rock mass characteristics around the opening; to determine the zone of blast damage; and to evaluate seismic methods for anomaly detection ahead of mining in this type of rock. The cross-hole measurements were made between four 76-mm diameter horizontal boreholes diamond-drilled 12 m into a wall of the underground opening. Repetitive pulses of compressional (P) and shear (S) waves of frequencies in the range 1 kHz-100 kHz were propagated from a transmitter sonde through the rock mass to a receiver sonde, both of which w~re clamped hydraulically to the borehole wall. After amplification the received P-and S-wave signals were digitized at the surface by a digital oscilloscope and stored on floppy discs.The results indicate considerable reductions in P-and S-wave velocities at distances less than 2 m from the face. Clearly these low values are associated with blast damage. Beyond 2 m, the velocities in a vertical direction indicate almost constant values. The velocities in the horizontal direction beyond 2m appeared erratic, but showed a general tendency to increase as a function of distance from the face. Their maximum values remained, however, still lower in value than the corresponding velocities in the vertical direction. Near the face, the differences in velocities were considerably greater: with horizontal velocities considerably lower in value than those v~rtical.

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Section: Methodsmentioning

confidence: 99%

Cross-hole acoustic measurements in basalt

Myer

Rezowalli

1986

International Journal of Rock Mechanics and Mining Sciences &am

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“…This relative rareness is partly due to: (i) the inherent difficulty of transmitting transducer signals through the waterproof pressure chamber in a loading apparatus ; and, on the other hand, (ii) the specificities in preparing and handling shale samples for mechanical testing (chemical sensitivity to water, extremely low permeability...). Most of the dynamic experimental studies reported in the literature on shale samples were performed under hydrostatic loading conditions (Johnston and Toksöz 1980;Jones and Wang 1981;Lo et al 1986;Johnston and Christensen 1995;Hornby 1998;Stanley and Christensen 2001). Only Yin (1992) carried out triaxial tests.…”

Section: Shale Lithologiesmentioning

confidence: 99%

Shale dynamic properties and anisotropy under triaxial loading

Sarout¹,

Molez²,

Guéguen³

et al. 2005

Poromechanics III - Biot Centennial (1905-2005)

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Nasser HoteitAgence Nationale pour la gestion des Déchets RAdioactifs, France. This paper is concerned with the experimental identification of the whole dynamic elastic stiffness tensor of a transversely isotropic clayrock from a single cylindrical sample under loading. Measurement of elastic wave velocities (pulse at 1 MHz), obtained under macroscopically undrained triaxial loading conditions are provided. Further interpretation of the velocity measurements is performed in terms of (i) dynamic elastic parameters ; and (ii) elastic anisotropy. A discussion concerning microcracks and fluid content (saturation) issues follows. Experiments were performed on a Callovo-Oxfordian shale, Jurassic in age, recovered from a depth of 613 m in the eastern part of Paris basin in France.

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“…Going from air-dry to fully fluid saturated case, attenuation increases (Johnston et al, 1980;Toksoz et al, 1979;Winkler and Nur, 1979). The largest effect of saturation occurs in Qs' In the air-dry case Q p '" Q s and, in fully saturated case Q s < Qp' Partial saturation may reduce Q p relative to full saturation, but this effect is generally small (Winkler and Nur, 1979;Johnston and Toksoz, 1980;Frisillo and Stewart, 1 980).…”

Section: Introductionmentioning

confidence: 99%

“…The contribution of pore fluid to attenuation in rocks has been a subject of interest and intensive study (Bulau et al, 1984;Murphy, 1982;Spencer, 1981;Winkler and Nur, 1979;Mavko and Nur, 1979;Johnston et al, 1979;Johnston and Toksoz, 1980;O'Connell and Budiansky, 1977;Biot, 1956a,b;Wyllie et al, 1962).…”

Section: Introductionmentioning

confidence: 99%

Laboratory measurements of attenuation in rocks at ultrasonic frequencies

Gonguet¹,

Coyner²,

Toksöz³

1985

SEG Technical Program Expanded Abstracts

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The spectral ratio method is used to calculate the quaiity factor (0) in porous rock samples at ultrasonic frequencies (0.3 -1.5 MHz). The data were ccllected using the pulse transmissicn technique with aluminum used as a high 0 standard. The data set ccnsists of dry, water and benzene saturated rocks at differentia! pressures from zero to one kilobar. Two sandstones, Berea and Kayenta, Bedfcrd limestone, and Webatuck dolomite are studied. Water and benzene were chosen as pore fluid saturants to contrast the effects of two different pore fluids (density, compressibility, viscosity, dielectric constant, and wetting properties) at ultrasonic frequencies. The main features observed are: 1) The quality factor 0 increases with increasing confining pressure; at low pressures the rate of increase is larger. 2) 0 for saturated samples is generally lower than for dry samples.3) The introduction of a fluid saturant into a dry rock increases S-wave attenuation more than P-wave attenuation. 4) In general, given the measurement error and the fact that these results are preliminary, the differences in attenuation between the two fluid saturations, water and benzene, are not large. Nevertheless, we observe that benzene-saturated attenuations are slightly higher than water-saturated vaiues, particularly at lower pressures (less than 500 bars) for the P-wave.

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Ultrasonic P and S wave attenuation in dry and saturated rocks under pressure

Cited by 172 publications

References 39 publications

Cross-hole acoustic measurements in basalt

Cross-hole acoustic measurements in basalt

Shale dynamic properties and anisotropy under triaxial loading

Laboratory measurements of attenuation in rocks at ultrasonic frequencies

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