Determination of the elastic wave velocities in porous rocks with the change of overburden pressure and its universal significance

2002 ◽  
Vol 45 (7) ◽  
pp. 635 ◽  
Author(s):  
Ge SHI
Keyword(s):  
Elastic Wave ◽  
Porous Rocks ◽  
Overburden Pressure ◽  
Wave Velocities

Incorporating mechanisms of fluid pressure relaxation into inclusion‐based models of elastic wave velocities

Geophysics ◽  
2003 ◽  
Vol 68 (4) ◽  
pp. 1173-1181 ◽  
Author(s):  
S. Richard Taylor ◽  
Rosemary J. Knight
Keyword(s):  
Elastic Wave ◽  
Water Saturation ◽  
Laboratory Data ◽  
Fluid Pressure ◽  
P Wave ◽  
Porous Rocks ◽  
Low Frequencies ◽  
Wave Velocities ◽  
Exact Agreement ◽  
Flow Through

Our new method incorporates fluid pressure communication into inclusion‐based models of elastic wave velocities in porous rocks by defining effective elastic moduli for fluid‐filled inclusions. We illustrate this approach with two models: (1) flow between nearest‐neighbor pairs of inclusions and (2) flow through a network of inclusions that communicates fluid pressure throughout a rock sample. In both models, we assume that pore pressure gradients induce laminar flow through narrow ducts, and we give expressions for the effective bulk moduli of inclusions. We compute P‐wave velocities and attenuation in a model sandstone and illustrate that the dependence on frequency and water‐saturation agrees qualitatively with laboratory data. We consider levels of water saturation from 0 to 100% and all wavelengths much larger than the scale of material heterogeneity, obtaining near‐exact agreement with Gassmann theory at low frequencies and exact agreement with inclusion‐based models at high frequencies.

scholarly journals Ultrasonic moduli for fluid-saturated rocks: Mavko-Jizba relations rederived and generalized

Geophysics ◽  
2009 ◽  
Vol 74 (4) ◽  
pp. N25-N30 ◽  
Author(s):  
Boris Gurevich ◽  
Dina Makarynska ◽  
Marina Pervukhina
Keyword(s):  
Elastic Wave ◽  
Bulk Modulus ◽  
Quantitative Model ◽  
Pore Fluid ◽  
Porous Rocks ◽  
Laboratory Measurements ◽  
Shear Moduli ◽  
Wave Velocities

Mavko and Jizba propose a quantitative model for squirt dispersion of elastic-wave velocities between seismic and ultrasonic frequencies in granular rocks. Their central results are the expressions for the so-called unrelaxed frame bulk and shear moduli computed under an assumption that the stiff pores are drained (or dry) but the soft pores are filled with fluid. Mavko-Jizba expressions are limited to liquid-saturated rocks but become inaccurate when the fluid-bulk modulus is small (e.g., for gas-saturated rocks). We have derived new expressions for unrelaxed moduli of fluid-saturated porous rocks using Sayers-Kachanov discontinuity formalism. The derived expressions generalize the established Mavko-Jizba relations to gas-saturated rocks, reduce to Mavko-Jizba results when the pore fluid is liquid, and yield dry moduli when fluid-bulk modulus tends to zero. We tested this by comparing our model and the model of Mavko and Jizba against laboratory measurements on a sample of Westerly granite.

Assessing rock brittleness and fracability from radial variation of elastic wave velocities from borehole acoustic logging

2016 ◽  
Vol 64 (4) ◽  
pp. 958-966 ◽  
Author(s):  
Xiao-Ming Tang ◽  
Song Xu ◽  
Chun-Xi Zhuang ◽  
Yuan-Da Su ◽  
Xue-Lian Chen
Keyword(s):  
Elastic Wave ◽  
Radial Variation ◽  
Acoustic Logging ◽  
Wave Velocities ◽  
Rock Brittleness

Elastic Wave Velocities in Laminated Media

1954 ◽  
Vol 26 (5) ◽  
pp. 949-949
Author(s):  
J. E. White ◽  
F. A. Angona
Keyword(s):  
Elastic Wave ◽  
Wave Velocities
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