Products

pore collapse and grain crushing on ultrasonic

Effects of pore collapse and grain crushing on ultrasonic

Aug 21, 2007· On both curves, the inflection point, P*, corresponds to the onset of grain crushing and pore collapse [Zhang et al., 1990; Wong et al., 1997], equal to 180 and 135 MPa, in the dry and wet experiment, respectively. Beyond P*, accelerating inelastic volume compaction occurs due to extensive grain crushing, grain displacement, and pore collapse

More

Effects of pore collapse and grain crushing on ultrasonic

Aug 21, 2007· Chao Sun, Jan V. M. Borgomano, Jérôme Fortin, ShangXu Wang, Effect of Pore Collapse and Grain Crushing on the Frequency Dependence of Elastic Wave Velocities in a Porous Sandstone, Rock Mechanics and Rock Engineering, 10.1007/s00603-020-02213-0,

More

(PDF) Effects of pore collapse and grain crushing on

50 pore collapse and grain crushing (nonlocalized cataclastic 51 flow) [ Zhang et al.,1990; W ong et al.,1997]. 52 [ 3 ] Recent field [ Mollema and Anto nellini,1996], and

More

Effects of pore collapse and grain crushing on ultrasonic

At a critical effective confining pressure P*, a large mechanical decrease of porosity was observed that was due to pore collapse and grain crushing. Theoretically, two different processes are affecting the elastic wave velocities in counteracting ways during cataclastic compaction: cracking and porosity decrease.

More

Effects of pore collapse and grain crushing on ultrasonic

2 Effects of pore collapse and grain crushing on 3 ultrasonic velocities and V p/V s 4 Je´roˆme Fortin,1 Yves Gue´guen,1 and Alexandre Schubnel2

More

Effect of Pore Collapse and Grain Crushing on the

Jul 29, 2020· A saturated Bleurswiller sandstone, of 25% porosity, was compacted by increasing the confining pressure over the critical pressure P* which characterizes the onset of pore collapse and grain crushing. The frequency-dependence of Young’s moduli were measured before and after the compaction using forced-oscillation method in a triaxial cell.

More

CiteSeerX — 2 Effects of pore collapse and grain crushing

At first, increase in hydrostatic pressure was 9 accompanied by a simultaneous increase of both Vp and Vs as expected. At a critical 10 effective confining pressure P*, a large mechanical decrease of porosity was observed that 11 was due to pore collapse and grain crushing.

More

Compaction bands due to grain crushing in porous rocks: A

Grain crushing and pore collapse are the principal micromechanisms controlling the physics of compaction bands in porous rocks. Several constitutive models have been previously used to predict the formation and propagation of these bands. However, they do not account directly for the physical processes of grain crushing and pore collapse. The parameters of these previous models were

More

Effect of pores and grain size on the elastic and

The role of grain size and porosity in the piezoelectric and elastic properties of SiO 2-based materials was investigated using resonant piezoelectric spectroscopy (RPS) and resonant ultrasound spectroscopy (RUS).RPS performed on agate revealed a piezoelectric effect comparable in magnitude to that in single-crystal quartz.

More

4.4 Compression failure: Pore collapse GitHub Pages

4. 4 Compression failure: Pore collapse. If compression stresses are high enough, grains can crush filling the pore space. Pore collapse may happen in nature due to rock burial and also in petroleum engineering during reservoir depletion. In both cases effective stresses increase in all directions.

More

Estimation of pore microstructure by using the static and

Jan 01, 2019· J. Fortin, Y. Guéguen, A. SchubnelEffects of pore collapse and grain crushing on ultrasonic velocities and Vp/Vs J Geophys Res: Solid Earth, 112 (2007), p. B08207

More

On the pore-scale mechanisms leading to brittle and

Various different ways to model pore collapse also have been proposed and among them, Wang et al. [29] used grain shrinkage to simulate intra-granular cracking and grain crushing processes. In these models, porosity is derived based on the spaces generated from the random assembly of the circular disks or spherical particles.

More

Effect of Loading Path and Porosity on the Failure Mode of

The onset of grain crushing and pore collapse was marked by a surge in acoustic emission activity. A Hertzian fracture mechanics model was formulated to analyze the roles of porosity, grain size and fracture toughness in controlling the onset of hydrostatic and shear-enhanced compaction. Stereological measurements of the microcrack density show

More

Influence of fluids on VP/VS ratio: increase or decrease

1 INTRODUCTION. The ratio of P- to S-wave velocities (V P /V S ratio) is commonly considered as a key constraint on the nature and composition of rocks when interpreting seismological data (e.g. Christensen 1996).It is also well established that the presence of fluid-filled porosity (cracks, pores or open grain junctions) strongly modifies the V P /V S ratio (e.g. Kuster & Toksöz 1974; O

More

Simulation of localized compaction in high-porosity

mechanics of compaction, such as bond/grain breakage and pore collapse. A notable exception is the work by Das et al. [16,21],inwhich the explicit incorporation of grain crushing allowed the authors to point out the importance of the rheological response on the simula-tion of both onset and propagation of compaction bands.

More

Effective Elastic Properties of Cracked Solids: An

May 14, 2013· Fortin, J., Y. Guéguen, and A. Schubnel (2007), Effects of pore collapse and grain crushing on ultrasonic velocities and vp/vs, Journal of geophysical research, 112, doi:10.129/2005JB004,005. Fortin J., Stanchits S., Vinciguerra S., Guéguen Y. (2011) Influence of thermal and mechanical cracks on permeability and elastic wave velocities in a

More

Characterizing the nonlinear interaction of S- and P-waves

Jan 16, 2015· The nonlinear elastic response of rocks is known to be caused by the rocks' microstructure, particularly cracks and fluids. This paper presents a method for characterizing the nonlinearity of rocks in a laboratory scale experiment with a unique configuration. This configuration has been designed to open up the possibility of using the nonlinear characterization of rocks as an

More

Pore pressure distribution along plate interface that

sudden decrease in permeability is induced by pore collapse beyond a critical pressure. Sometimes, there was a sharp drop in permeability by about three orders of magnitude immediately following the onset of pore collapse and grain crushing at the critical pressure. We take this pore collapse into account when calculating pore pressure

More

X-Ray Imaging for Compaction Band Characterisation in

Aug 17, 2015· o grain crushing and pore collapse Challenge o to study compaction bands at the laboratory scale using a combination of advanced non-destructive experimental methods Focus herein o x-ray imaging (density variations) Study material Vosges sandstone o ~22% porosity o 93% quartz, 5% feldspar, 1% kaolinite, 1% mica (+ some oxides)

More

Evolution of hydraulic and elastic properties of reservoir

May 01, 2019· The CT values of individual pores indicate that the grayscale value changes gradually from the grain boundary to the pore center (Jiang and Tsuji, 2014), A. SchubnelEffects of pore collapse and grain crushing on ultrasonic velocities and Vp/Vs. J. Geophys. Res., 112 (2007), p. B08207, 10.1029/2005JB004005.

More

solid/fluid substitution scheme constrained by pore-scale

To ensure Gassmann consistency, Glubokovskikh et al. modelled the compliant pores as grain-to-grain contacts open into stiff pores. Compliant pores are modelled as thin circular disks with traction-free edges. The Effects of pore collapse and grain crushing on ultrasonic velocities and Vp/Vs, J.

More