Seismic-frequency loss mechanisms: Direct observation

Batzle, Michael; Kumar, Gautam; Hofmann, Ronny; Duranti, Luca; Adam, Ludmila

doi:10.1190/tle33060656.1

Cited by 15 publications

(4 citation statements)

References 9 publications

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“…Is it the case for fluid-saturated rocks? In such materials, various loss mechanisms have been identified, such as (Batzle et al, 2014) squirt flow in fully saturated rocks, pocket flow in partially saturated rocks, or even intrinsic loss in the fluid phase alone. Experimental methods were devised to better characterize those effects, one of which is the stress-strain (or forced-deformation) method.…”

Section: Introductionmentioning

confidence: 99%

Dispersions and attenuations in a fully saturated sandstone: Experimental evidence for fluid flows at different scales

et al. 2016

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Dispersion and attenuation of elastic waves have been observed in crustal rocks. Existing theories and experimental measurements evidenced the existence of different energy-loss mechanisms. In rocks fully saturated by a Newtonian fluid, one major candidate is fluid flow at different scales, separating three regimes: the drained, undrained, and unrelaxed regimes. Here, two elastic transitions, between these three regimes, are investigated. Both the cause and the consequence of the drained/ undrained transition are evidenced. Because the second transition measured occurs at higher frequency, where no global fluid flow occurs, it in turn is associated to the undrained/unrelaxed transition (or squirt flow). For both transitions, the amount of open microcracks seems to be the major contributor to the magnitudes of attenuation.

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Section: Introductionmentioning

confidence: 99%

Dispersions and attenuations in a fully saturated sandstone: Experimental evidence for fluid flows at different scales

et al. 2016

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“…From a more general perspective, in spite of the very low permeability characteristics, shales are heterogeneous porous rocks, more or less containing elastic heterogeneities. Frequency-dependent elastic behaviors of shales based on the laboratory measurements have been reported by Jones and Wang (1981), Duranti et al (2005), Hofmann (2006, Batzle et al (2014), and Bauer et al (2016). Therefore, shales should also be considered as naturally dispersive geomaterials, even their characteristic frequency might occur at very low frequency range since it takes extremely long time to achieve pore pressure equilibration (Batzle et al, 2006).…”

Section: Parameterization Of the Patchy Saturation Reservoir Model 2mentioning

confidence: 96%

“…Moreover, note that this is the velocity dispersion caused by pure fluids. The heavy oil-filled sands have even smaller dispersion than the heavy oil itself (Batzle et al, 2014). In practice, heavy oils in the glassy solid status are considered as elastic, and the velocity dispersion mainly occurs at the quasi-liquid status (Han et al, 2008).…”

Section: Seismic Attenuation Caused By Heavy Oilmentioning

confidence: 99%

“…By using visual inspection of partially saturated limestones, Cadoret et al (1995) presented the dependence of measured compressional velocity upon frequency and fluid distribution. Batzle et al (2006Batzle et al ( , 2014 presented the frequency-dependent velocity characteristic in a partially saturated rock using a forced deformation system. Tisato and Quintal (2013) reported measurements of frequency-dependent dispersion and attenuation in partially saturated Berea sandstone to shed light on the evidence of fluid flow on the mesoscopic scale.…”

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confidence: 99%

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Mobility Effect on Poroelastic Seismic Signatures in Partially Saturated Rocks With Applications in Time‐Lapse Monitoring of a Heavy Oil Reservoir

et al. 2017

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Conventional seismic analysis in partially saturated rocks normally lays emphasis on estimating pore fluid content and saturation, typically ignoring the effect of mobility, which decides the ability of fluids moving in the porous rocks. Deformation resulting from a seismic wave in heterogeneous partially saturated media can cause pore fluid pressure relaxation at mesoscopic scale, thereby making the fluid mobility inherently associated with poroelastic reflectivity. For two typical gas‐brine reservoir models, with the given rock and fluid properties, the numerical analysis suggests that variations of patchy fluid saturation, fluid compressibility contrast, and acoustic stiffness of rock frame collectively affect the seismic reflection dependence on mobility. In particular, the realistic compressibility contrast of fluid patches in shallow and deep reservoir environments plays an important role in determining the reflection sensitivity to mobility. We also use a time‐lapse seismic data set from a Steam‐Assisted Gravity Drainage producing heavy oil reservoir to demonstrate that mobility change coupled with patchy saturation possibly leads to seismic spectral energy shifting from the baseline to monitor line. Our workflow starts from performing seismic spectral analysis on the targeted reflectivity interface. Then, on the basis of mesoscopic fluid pressure diffusion between patches of steam and heavy oil, poroelastic reflectivity modeling is conducted to understand the shift of the central frequency toward low frequencies after the steam injection. The presented results open the possibility of monitoring mobility change of a partially saturated geological formation from dissipation‐related seismic attributes.

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Resonant ultrasound spectroscopy of horizontal transversely isotropic samples

Watson

Wijk

2015

JGR Solid Earth

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Most crustal rocks present some amount of directional dependence of seismic speeds, particularly mudstones (also termed "shales"). Hence, accurate imaging of the subsurface requires anisotropic models and integration of rock physics information in order to constrain the inherent nonuniqueness of the inversion from seismic data. Resonant ultrasound spectroscopy provides estimates of the full anisotropic stiffness tensor from resonant frequencies of geological core samples, along with a measure of intrinsic attenuation. We have developed new functionality to existing codes which enable horizontal transversely isotropic samples to be analyzed. We compared and discussed estimations of the elastic properties of mudstone samples with hexagonal symmetry; one sample was drilled parallel and one perpendicular to the layering. While spatial heterogeneity in the mudstone prevented a direct correlation of the elastic parameters of each sample, time-of-flight measurements reveal frequency dispersion of the elastic parameters that is consistent between the samples.

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Seismic-frequency loss mechanisms: Direct observation

Cited by 15 publications

References 9 publications

Dispersions and attenuations in a fully saturated sandstone: Experimental evidence for fluid flows at different scales

Dispersions and attenuations in a fully saturated sandstone: Experimental evidence for fluid flows at different scales

Mobility Effect on Poroelastic Seismic Signatures in Partially Saturated Rocks With Applications in Time‐Lapse Monitoring of a Heavy Oil Reservoir

Resonant ultrasound spectroscopy of horizontal transversely isotropic samples

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