Seismic attenuation in partially saturated rocks: Recent advances and future directions

Tisato, Nicola; Quintal, Beatriz; Chapman, Samuel; Madonna, Claudio; Subramaniyan, Shankar; Frehner, Marcel; Saenger, Erik H.; Grasselli, Giovanni

doi:10.1190/tle33060640.1

Cited by 29 publications

(8 citation statements)

References 11 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Waves generate fluid flow in the pores and energy losses that can be observed in field and laboratory experiments [2][3][4]. Recent laboratory experiments performed in the seismic range have shown the frequency dependence of anelasticity in sandstones with partial gas or oil saturations [5][6][7], while experiments conducted in Reference [8] show a significant attenuation in the extensional and bulk deformation modes, as well as numerical simulations in close agreement with laboratory data.…”

Section: Introductionsupporting

confidence: 64%

Two-Phase Flow Effects on Seismic Wave Anelasticity in Anisotropic Poroelastic Media

Santos

Carcione

2021

Energies

View full text Add to dashboard Cite

We study the wave anelasticity (attenuation and velocity dispersion) of a periodic set of three flat porous layers saturated by two immiscible fluids. The fluids are very dissimilar in properties, namely gas, oil, and water, and, at most, three layers are required to study the problem from a general point of view. The sequence behaves as viscoelastic and transversely isotropic (VTI) at wavelengths much longer than the spatial period. Wave propagation causes fluid flow and slow P modes, inducing anelasticity. The fluids are characterized by capillary forces and relative permeabilities, which allow for the existence of two slow modes and the presence of dissipation, respectively. The methodology to study the physics is based on a finite-element uspcaling approach to compute the complex and frequency-dependent stiffnesses of the effective VTI medium. The results of the experiments indicate that there is higher dissipation and anisotropy compared to the widely used model based on an effective fluid that ignores the effects of surface tension (capillarity) and viscous flow interference between the two fluid phases.

show abstract

Section: Introductionsupporting

confidence: 64%

Two-Phase Flow Effects on Seismic Wave Anelasticity in Anisotropic Poroelastic Media

Santos

Carcione

2021

Energies

View full text Add to dashboard Cite

show abstract

“…Nevertheless, wave attenuation characteristics at sonic and ultrasonic frequencies cannot be simply extrapolated to the field‐scale data due to the expected frequency dependency. To make laboratory measurement more closely related to the frequency range of field seismic data, the forced‐oscillation technique was devised to dynamically measure the frequency‐dependent elastic moduli within a broad frequency range (i.e., 10 −3 to kHz) (e.g., Batzle et al, 2006; Fortin et al, 2005, 2014; Madonna et al, 2011; Mikhaltsevitch et al, 2011; Piane et al, 2019; Pimienta et al, 2015a; Quintal et al, 2013; Spencer, 1981; Tisato et al, 2014; Zhao et al, 2013).…”

Section: Introductionmentioning

confidence: 99%

Role of Saturation on Elastic Dispersion and Attenuation of Tight Rocks: An Experimental Study

Wang

Gao

et al. 2020

JGR Solid Earth

View full text Add to dashboard Cite

Using the forced-oscillation method, we measure the dispersion of Young's modulus, extensional attenuation, and Poisson's ratio of tight sandstone and carbonate samples at seismic frequencies (1-1000 Hz) under a constant confining pressure of 20 MPa and for a water saturation varying between 0% and 100%. The experimental data suggest that the dispersion of Young's modulus and attenuation of tight rocks is significant in a broad frequency band spanning over 1-1000 Hz. A comparison with the high-porosity and high-permeability sample data shows a contrasting dispersion and attenuation characteristics. For the tight sandstone, Young's modulus reaches a maximum dispersion of 16% at 60% water saturation and a 13% dispersion at 100% saturation. Attenuation is insignificant in dry condition and for water saturation ≤30%. In contrast with the peak attenuation occurring at very high water saturation (e.g., 80-100%) in partially saturated high-porosity rocks, peak attenuation of tight sandstone takes place at a water saturation of 60%. For the tight carbonate, the magnitude of dispersion (~3%) and attenuation are markedly lower for all saturation levels. In the explored frequency range (1-1000 Hz), Young's modulus increases monotonously, and no obvious attenuation peak is observed when saturation levels are greater than 10%. Using well-established theoretical models based on physical properties and microstructure of the tested rocks, we suggest that the observed attenuation characteristics are possibly attributed to the combined physical mechanism of microscopic (squirt) flow, mesoscopic flow in partially saturated rock, and shear dispersion due to viscous flow in grain contacts. Key Points:• Dispersion and attenuation of both tight sandstone and carbonate are distributed across frequency range of 1-1000 Hz • Extensional attenuation in tight sandstone is saturation dependent with a maximum at 60% saturation, which contrasts with that of porous sandstones • The coupled pore fabric and fluid distribution heterogeneity in tight rocks might cause complex dispersion and attenuation characteristics

show abstract

“…∼5 cm in length) than that in the resonance bar technique (e.g. ∼50 cm in length) (Fortin et al ., 2005, 2007; Batzle et al, 2006; Madonna et al ., 2011; Mikhaltsevitch et al ., 2011; Quintal et al ., 2013; Subramaniyan et al ., 2014; Tisato et al ., 2014; Pimienta et al ., 2015a). Basically, the induced strain amplitude of the forced‐oscillation device should be less than 10 −6 to achieve the elastic response of far‐field seismic waves, with the coverage of a wide frequency band (e.g.…”

Section: Introductionmentioning

confidence: 99%

Experimental study on frequency‐dependent elastic properties of weakly consolidated marine sandstone: effects of partial saturation

Zhao

Han

et al. 2020

Geophysical Prospecting

View full text Add to dashboard Cite

Investigating seismic dispersion and attenuation characteristics of loosely compacted marine sandstone is essential in reconciling different geophysical measurements (surface seismic, well logging and ultrasonic) for better characterization of a shallow marine sandstone reservoir. We have experimented with a typical high-porosity and highpermeability sandstone sample, extracted from the Paleogene marine depositional setting in the Gulf of Mexico, at the low-frequency band (2-500 Hz) as well as ultrasonic point (10 6 Hz), to investigate the effects of varying saturation levels on a rock's elasticity. The results suggest that the Young's modulus of the measured sample with adsorbed moisture at laboratory conditions (room temperature, 60%-90% humidity) exhibits dispersive behaviours. The extensional attenuation can be as high as 0.038, and the peak frequency occurs around 60 Hz. The extensional attenuation due to moisture adsorption can be dramatically mitigated with the increase of confining pressure. For partial saturation status, extensional attenuation increases as increasing water saturation by 79% with respect to the measured frequencies. Additionally, the results show that extensional attenuation at the fully water-saturated situation is even smaller than that at adsorbed moisture conditions. The Gassmann-Wood model can overall capture the P-wave velocity-saturation trend of measured data at seismic frequencies, demonstrating that the partially saturated unconsolidated sandstone at the measured seismic frequency range is prone to be in the relaxed status. Nevertheless, the ultrasonic velocities are significantly higher than the Gassmann-Wood predictions, suggesting that the rocks are in the unrelaxed status at the ultrasonic frequency range. The poroelastic modelling results based on the patchy saturation model also indicate that the characteristic frequency of the partially saturated sample is likely beyond the measured seismic frequency range.

show abstract

Seismic attenuation in partially saturated rocks: Recent advances and future directions

Cited by 29 publications

References 11 publications

Two-Phase Flow Effects on Seismic Wave Anelasticity in Anisotropic Poroelastic Media

Two-Phase Flow Effects on Seismic Wave Anelasticity in Anisotropic Poroelastic Media

Role of Saturation on Elastic Dispersion and Attenuation of Tight Rocks: An Experimental Study

Experimental study on frequency‐dependent elastic properties of weakly consolidated marine sandstone: effects of partial saturation

Contact Info

Product

Resources

About