Influence of pressure, temperature, and pore fluid on the frequency-dependent attenuation of elastic waves in Berea sandstone

1985 ◽  
Vol 32 (1) ◽  
pp. 472-488 ◽  
Author(s):  
Stephen G. O’Hara
Keyword(s):  
Elastic Waves ◽  
Pore Fluid ◽  
Berea Sandstone ◽  
Frequency Dependent

scholarly journals Fluid Discrimination Based on Frequency-Dependent AVO Inversion with the Elastic Parameter Sensitivity Analysis

Geofluids ◽  
2019 ◽  
Vol 2019 ◽  
pp. 1-13
Author(s):  
Pu Wang ◽  
Jingye Li ◽  
Xiaohong Chen ◽  
Kedong Wang ◽  
Benfeng Wang
Keyword(s):  
Data Interpretation ◽  
Elastic Parameter ◽  
Pore Fluid ◽  
P Wave ◽  
Frequency Dependent ◽  
Avo Inversion ◽  
Fluid Factor ◽  
Dispersion Terms ◽  
Dispersion And Attenuation ◽  
Dispersion Term

Fluid discrimination is an extremely important part of seismic data interpretation. It plays an important role in the refined description of hydrocarbon-bearing reservoirs. The conventional AVO inversion based on Zoeppritz’s equation shows potential in lithology prediction and fluid discrimination; however, the dispersion and attenuation induced by pore fluid are not fully considered. The relationship between dispersion terms in different frequency-dependent AVO equations has not yet been discussed. Following the arguments of Chapman, the influence of pore fluid on elastic parameters is analyzed in detail. We find that the dispersion and attenuation of Russell fluid factor, Lamé parameter, and bulk modulus are more pronounced than those of P-wave modulus. The Russell fluid factor is most prominent among them. Based on frequency-dependent AVO inversion, the uniform expression of different dispersion terms of these parameters is derived. Then, incorporating the P-wave difference with the dispersion terms, we obtain new P-wave difference dispersion factors which can identify the gas-bearing reservoir location better compared with the dispersion terms. Field data application also shows that the dispersion term of Russell fluid factor is optimal in identifying fluid. However, the dispersion term of Russell fluid factor could be unsatisfactory, if the value of the weighting parameter associated with dry rock is improper. Then, this parameter is studied to propose a reasonable setting range. The results given by this paper are helpful for the fluid discrimination in hydrocarbon-bearing rocks.

Anisotropic P-SV-wave dispersion and attenuation due to inter-layer flow in thinly layered porous rocks

Geophysics ◽  
2011 ◽  
Vol 76 (3) ◽  
pp. WA135-WA145 ◽  
Author(s):  
Fabian Krzikalla ◽  
Tobias M. Müller
Keyword(s):  
Wave Attenuation ◽  
Fluid Pressure ◽  
Pore Fluid ◽  
P Wave ◽  
Angle Of Incidence ◽  
Porous Rocks ◽  
Frequency Dependent ◽  
Symmetry Properties ◽  
Wave Induced ◽  
Attenuation And Dispersion

Elastic upscaling of thinly layered rocks typically is performed using the established Backus averaging technique. Its poroelastic extension applies to thinly layered fluid-saturated porous rocks and enables the use of anisotropic effective medium models that are valid in the low- and high-frequency limits for relaxed and unrelaxed pore-fluid pressures, respectively. At intermediate frequencies, wave-induced interlayer flow causes attenuation and dispersion beyond that described by Biot’s global flow and microscopic squirt flow. Several models quantify frequency-dependent, normal-incidence P-wave propagation in layered poroelastic media but yield no prediction for arbitrary angles of incidence, or for S-wave-induced interlayer flow. It is shown that generalized models for P-SV-wave attenuation and dispersion as a result of interlayer flow can be constructed by unifying the anisotropic Backus limits with existing P-wave frequency-dependent interlayer flow models. The construction principle is exact and is based on the symmetry properties of the effective elastic relaxation tensor governing the pore-fluid pressure diffusion. These new theories quantify anisotropic P- and SV-wave attenuation and velocity dispersion. The maximum SV-wave attenuation is of the same order of magnitude as the maximum P-wave attenuation and occurs prominently around an angle of incidence of [Formula: see text]. For the particular case of a periodically layered medium, the theoretical predictions are confirmed through numerical simulations.

scholarly journals Experimental Measurement of Frequency-Dependent Permeability and Streaming Potential of Sandstones

2019 ◽  
Vol 131 (2) ◽  
pp. 333-361 ◽  
Author(s):  
P. W. J. Glover ◽  
R. Peng ◽  
P. Lorinczi ◽  
B. Di
Keyword(s):  
Porous Media ◽  
Elastic Waves ◽  
Fluid Pressure ◽  
Streaming Potential ◽  
Transition Frequency ◽  
High Porosity ◽  
Critical Transition ◽  
Potential Coefficient ◽  
Frequency Dependent ◽  
Dynamic Permeability

Abstract Hydraulic flow, electrical flow and the passage of elastic waves through porous media are all linked by electrokinetic processes. In its simplest form, the passage of elastic waves through the porous medium causes fluid to flow through that medium and that flow gives rise to an electrical streaming potential and electrical counter-current. These processes are frequency-dependent and governed by coupling coefficients which are themselves frequency-dependent. The link between fluid pressure and fluid flow is described by dynamic permeability, which is characterised by the hydraulic coupling coefficient (Chp). The link between fluid pressure and electrical streaming potential is characterised by the streaming potential coefficient (Csp). While the steady-state values of such coefficients are well studied and understood, their frequency dependence is not. Previous work has been confined to unconsolidated and disaggregated materials such as sands, gravels and soils. In this work, we present an apparatus for measuring the hydraulic and streaming potential coefficients of high porosity, high permeability consolidated porous media as a function of frequency. The apparatus operates in the range 1 Hz to 2 kHz with a sample of 10 mm diameter and 5–30 mm in length. The full design and validation of the apparatus are described together with the experimental protocol it uses. Initial data are presented for three samples of Boise sandstone, which present as dispersive media with the critical transition frequency of 918.3 ± 99.4 Hz. The in-phase and in-quadrature components of the measured hydraulic and streaming potential coefficients have been compared to the Debye-type dispersion model as well as theoretical models based on bundles of capillary tubes and porous media. Initial results indicate that the dynamic permeability data present an extremely good fit to the capillary bundle and Debye-type dispersion models, while the streaming potential coefficient presents an extremely good fit to all of the models up to the critical transition frequency, but diverges at higher frequencies. The streaming potential coefficient data are best fitted by the Pride model and its Walker and Glover simplification. Characteristic pore size values calculated from the measured critical transition frequency fell within 1.73% of independent measures of this parameter, while the values calculated directly from the Packard model showed an underestimation by about 12%.

scholarly journals Attenuation of Seismic Waves in Partially Saturated Berea Sandstone as a Function of Frequency and Confining Pressure

2021 ◽  
Vol 9 ◽  
Author(s):  
Nicola Tisato ◽  
Claudio Madonna ◽  
Erik H. Saenger
Keyword(s):  
Fluid Flow ◽  
Wave Attenuation ◽  
Confining Pressure ◽  
Berea Sandstone ◽  
Experimental Conditions ◽  
Frequency Dependent ◽  
Near Surface ◽  
Partially Saturated ◽  
Near Surface Geophysics ◽  
Wave Induced

Frequency-dependent attenuation (1/Q) should be used as a seismic attribute to improve the accuracy of seismic methods and imaging of the subsurface. In rocks, 1/Q is highly sensitive to the presence of saturating fluids. Thus, 1/Q could be crucial to monitor volcanic and hydrothermal domains and to explore hydrocarbon and water reservoirs. The experimental determination of seismic and teleseismic attenuation (i.e., for frequencies < 100 Hz) is challenging, and as a consequence, 1/Q is still uncertain for a broad range of lithologies and experimental conditions. Moreover, the physics of elastic energy absorption (i.e., 1/Q) is often poorly constrained and understood. Here, we provide a series of measurements of seismic wave attenuation and dynamic Young’s modulus for dry and partially saturated Berea sandstone in the 1–100 Hz bandwidth and for confining pressure ranging between 0 and 20 MPa. We present systematic relationships between the frequency-dependent 1/Q and the liquid saturation, and the confining pressure. Data in the seismic bandwidth are compared to phenomenological models, ultrasonic elastic properties and theoretical models for wave-induced-fluid-flow (i.e., squirt-flow and patchy-saturation). The analysis suggests that the observed frequency-dependent attenuation is caused by wave-induced-fluid-flow but also that the physics behind this attenuation mechanism is not yet fully determined. We also show, that as predicted by wave-induced-fluid-flow theories, attenuation is strongly dependent on confining pressure. Our results can help to interpret data for near-surface geophysics to improve the imaging of the subsurface.

On: “Lithology discrimination for thin layers using wavelet signal parameters” by J. N. Lange and H. A. Almoghrabi (GEOPHYSICS, 53, 1512–1519, December 1988).

Geophysics ◽  
1989 ◽  
Vol 54 (6) ◽  
pp. 789-789 ◽  
Author(s):  
M. K. Sengupta
Keyword(s):  
Pore Fluid ◽  
Thin Layers ◽  
Fluid Type ◽  
Frequency Dependent ◽  
Signal Parameters

Lange and Almoghrabi have shown correctly that seismic frequency is an important parameter for discriminating among seismic lithologies and pore‐fluid types for thin layers. I would like to draw attention to Figure 3 of this paper and to the last paragraph of their conclusions, which state, “The crux of the multiparameter algorithms…is the thin layer’s frequency‐dependent reflectivity, which can be used to discriminate reflector lithologies and pore fluid type.”

scholarly journals Laboratory observations of frequency-dependent ultrasonic P-wave velocity and attenuation during methane hydrate formation in Berea sandstone

2019 ◽  
Vol 219 (1) ◽  
pp. 713-723 ◽  
Author(s):  
Sourav K Sahoo ◽  
Laurence J North ◽  
Hector Marín-Moreno ◽  
Tim A Minshull ◽  
Angus I Best
Keyword(s):  
Aspect Ratio ◽  
Wave Velocity ◽  
Methane Hydrate ◽  
Hydrate Formation ◽  
P Wave ◽  
Gas Bubble ◽  
Berea Sandstone ◽  
Frequency Dependent ◽  
P Wave Velocity ◽  
Hydrate Saturation

SUMMARY Knowledge of the effect of methane hydrate saturation and morphology on elastic wave attenuation could help reduce ambiguity in seafloor hydrate content estimates. These are needed for seafloor resource and geohazard assessment, as well as to improve predictions of greenhouse gas fluxes into the water column. At low hydrate saturations, measuring attenuation can be particularly useful as the seismic velocity of hydrate-bearing sediments is relatively insensitive to hydrate content. Here, we present laboratory ultrasonic (448–782 kHz) measurements of P-wave velocity and attenuation for successive cycles of methane hydrate formation (maximum hydrate saturation of 26 per cent) in Berea sandstone. We observed systematic and repeatable changes in the velocity and attenuation frequency spectra with hydrate saturation. Attenuation generally increases with hydrate saturation, and with measurement frequency at hydrate saturations below 6 per cent. For hydrate saturations greater than 6 per cent, attenuation decreases with frequency. The results support earlier experimental observations of frequency-dependent attenuation peaks at specific hydrate saturations. We used an effective medium rock-physics model which considers attenuation from gas bubble resonance, inertial fluid flow and squirt flow from both fluid inclusions in hydrate and different aspect ratio pores created during hydrate formation. Using this model, we linked the measured attenuation spectral changes to a decrease in coexisting methane gas bubble radius, and creation of different aspect ratio pores during hydrate formation.

Elastic‐wave attenuation in fluid‐saturated Berea sandstone

Geophysics ◽  
1989 ◽  
Vol 54 (6) ◽  
pp. 785-788 ◽  
Author(s):  
Stephen G. O’Hara
Keyword(s):  
Empirical Study ◽  
Elastic Wave ◽  
Elastic Waves ◽  
Wave Attenuation ◽  
Fluid Pressure ◽  
External Pressure ◽  
Berea Sandstone ◽  
Pore Fluid Pressure ◽  
Brine Solution ◽  
Two Fluids

In a previous publication (O’Hara, 1985), I presented detailed measurements on the attenuation of elastic waves in fluid‐saturated Berea sandstone. These measurements were used in a systematic empirical study of the frequency dependence of attenuation as a function of external pressure applied to the sandstone, pore fluid pressure, and the saturated sandstone temperature. Two pore fluids were used in the study: a brine solution and n-heptane. I measured the attenuation of the extensional and torsional rod modes of cylindrical specimens of the sandstone at identical conditions of pressure and temperature for each of the two fluids.

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