Geomechanical Rock Properties Using Pressure and Temperature Dependence of Elastic P- and S-Wave Velocities

Motra, Hem Bahadur; Stutz, Hans Henning

doi:10.1007/s10706-018-0569-9

Cited by 21 publications

(18 citation statements)

References 21 publications

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“…We found that as the P-and S-wave velocities increased the elastic modulus also increased. Similarly, according to the results published by Motra and Stutz [30], the dynamic modulus of the elasticity increases with an increase in the wave velocity. Also, in this research, the class, range and…”

Section: Determination Of the Dynamic Elastic Modulus Using Ndtsupporting

confidence: 76%

Microstructural Characterization and Mechanical Properties of Volcanic Tuff (Malatya, Turkey) Used as Building Stone for the Restoring Cultural Heritage

Maraş

Köse

Rızaoğlu

2020

Period. Polytech. Civil Eng.

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Old stone buildings constitute a significant percentage of the residential buildings in many countries. These structures are highly vulnerable, and important losses in masonry structures occur even in moderate earthquakes. Therefore, safety evaluations of these structures have gained significant attention in recent years. In this study, the mechanical, physical and microstructural characteristics of tuff samples used in the old buildings were investigated in Battalgazi within the boundaries of Malatya Province during the Seljuk time. The characteristics of the building materials were examined in detail using in-situ and laboratory tests. Because adequate samples could not be obtained from the historical buildings, quarry areas with the same characteristics were identified. First, original building stone (OBS) used in construction was taken from fallen and unusable blocks. Then, the properties of the restoration building stones (RBS) brought from the quarries were investigated. The RBS samples were also examined using in the laboratory, and the mechanical and microstructural properties of the building components were determined. The dynamic and static moduli of elasticity were determined using ultrasonic pulse velocity and uniaxial compression test. The OBS and RBS samples yielded similar results after the microstructural analyses. Our results showed that the dynamic elastic modulus value was higher than the static elastic modulus value. The results revealed by both methods showed that the static and dynamic elastic moduli were closely linked. The OBS and RBS samples exhibited microlitic porphyritic and vesicular textures and nearly the same mineralogical and textural characteristics.

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Section: Determination Of the Dynamic Elastic Modulus Using Ndtsupporting

confidence: 76%

Microstructural Characterization and Mechanical Properties of Volcanic Tuff (Malatya, Turkey) Used as Building Stone for the Restoring Cultural Heritage

Maraş

Köse

Rızaoğlu

2020

Period. Polytech. Civil Eng.

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“…Scratch tests were conducted to obtain the UCS. Ultrasonic pulse velocity (UPV) was used to obtain the sonic velocities, which can be used to calculate the dynamic elastic moduli of the core samples (E, υ, λ, G, K, and H) as the change in wave velocities controls the rock geomechanical properties [32]. The experimental work procedures were performed as follows:…”

Section: Methodsmentioning

confidence: 99%

“…Motra and Stutz [32] showed that the dynamic elastic moduli (E, K, and G) of the metamorphic rocks (quartz mica schist, and amphibolite) were found to be a function of pressure and temperature. The sonic data results showed that P and S wave velocities increased with pressure increase and decreased with temperature increase.…”

Section: Of 18mentioning

confidence: 99%

“…The microcline as clay materials displayed a swelling effect because of the invaded filtrate into the rock; the behavior increased with increasing the exposure time; and therefore, the rock cohesion and integrity changed and affected the rock strength as it might cause changes in the bonding forces between the solid particles [24]. The internal topography changes affect the propagation of the sonic waves (Vp and Vs) through the rock samples, and as a result, there is an alteration in the rock geomechanics in terms of the dynamic elastic moduli [32]. The NMR cumulative T 2 results showed a reduction in the porosity system with time because of barite particles precipitations and swelling effect.…”

Section: Development Of New Correlations For Geomechanical Parametersmentioning

confidence: 99%

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Exposure Time Impact on the Geomechanical Characteristics of Sandstone Formation during Horizontal Drilling

et al. 2020

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The rock geomechanical properties are the key parameters for designing the drilling and fracturing operations and for programing the geomechanical earth models. During drilling, the horizontal-section drilling fluids interact with the reservoir rocks in different exposure time, and to date, there is no comprehensive work performed to study the effect of the exposure time on the changes in sandstone geomechanical properties. The objective of this paper is to address the exposure time effect on sandstone failure parameters such as unconfined compressive strength, tensile strength, acoustic properties, and dynamic elastic moduli while drilling horizontal sections using barite-weighted water-based drilling fluid. To simulate the reservoir conditions, Buff Berea sandstone core samples were exposed to the drilling fluid (using filter press) under 300 psi differential pressure and 200 °F temperature for different exposure times (up to 5 days). The rock characterization and geomechanical parameters were evaluated as a function of the exposure time. Scratch test was implemented to evaluate rock strength, while ultrasonic pulse velocity was used to obtain the sonic data to estimate dynamic elastic moduli. The rock characterization was accomplished by X-ray diffraction, nuclear magnetic resonance, and scanning electron microscope. The study findings showed that the rock compression and tensile strengths reduced as a function of exposure time (18% and 19% reduction for tensile strength and unconfined compression strength, respectively, after 5 days), while the formation damage displayed an increasing trend with time. The sonic results demonstrated an increase in the compressional and shear wave velocities with increasing exposure time. All the dynamic elastic moduli showed an increasing trend when extending the exposure time except Poisson’s ratio which presented a constant behavior after 1 day. Nuclear magnetic resonance results showed 41% porosity reduction during the five days of mud interaction. Scanning electron microscope images showed that the rock internal surface topography and internal integrity changed with exposure time, which supported the observed strength reduction and sonic variation. A new set of empirical correlations were developed to estimate the dynamic elastic moduli and failure parameters as a function of the exposure time and the porosity with high accuracy.

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“…For crystalline, metamorphic rocks, the effect of volume expansion is relatively small. Microcracks can be either randomly distributed or show a preferred orientation relative to the rock microstructure or to the stress field around the borehole (Dresen and Guéguen, 2004;Nur and Simmons, 1969). Our simulation of velocities under crack-related and crack-free conditions (Fig.…”

Section: Characteristics Of Core and Downhole Logging Vp Measurementsmentioning

confidence: 99%

Correlation of core and downhole seismic velocities in high-pressure metamorphic rocks: A case study for the COSC-1 borehole, Sweden

Kästner¹,

Pierdominici²,

Elger³

et al. 2020

Preprint

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<p>Deeply rooted thrust zones are key features of tectonic processes and the evolution of mountain belts. Exhumed and deeply-eroded orogens like the Scandinavian Caledonides allow to study such systems from the surface. Previous seismic investigations of the Seve Nappe Complex have shown indications for a strong but discontinuous reflectivity of this thrust zone, which is only poorly understood. The correlation of seismic properties measured on borehole cores with surface seismic data can help to constrain the origin of this reflectivity. In this study, we compare seismic velocities measured on cores to in situ velocities measured in the borehole. The core and downhole velocities deviate by up to 2 km/s. However, velocities of mafic rocks are generally in close agreement. Seismic anisotropy increases from about 5 to 26 % at depth, indicating a transition from gneissic to schistose foliation. Differences in the core and downhole velocities are most likely the result of microcracks due to depressurization of the cores. Thus, seismic velocity can help to identify mafic rocks on different scales whereas the velocity signature of other lithologies is obscured in core-derived velocities. Metamorphic foliation on the other hand has a clear expression in seismic anisotropy. To further constrain the effects of mineral composition, microstructure and deformation on the measured seismic anisotropy, we conducted additional microscopic investigations on selected core samples. These analyses using electron-based microscopy and X-ray powder diffractometry indicate that the anisotropy is strongest for mica schists followed by amphibole-rich units. This also emphasizes that seismic velocity and anisotropy are of complementary importance to better distinguish the present lithological units. Our results will aid in the evaluation of core-derived seismic properties of high-grade metamorphic rocks at the COSC-1 borehole and elsewhere.</p>

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Geomechanical Rock Properties Using Pressure and Temperature Dependence of Elastic P- and S-Wave Velocities

Cited by 21 publications

References 21 publications

Microstructural Characterization and Mechanical Properties of Volcanic Tuff (Malatya, Turkey) Used as Building Stone for the Restoring Cultural Heritage

Microstructural Characterization and Mechanical Properties of Volcanic Tuff (Malatya, Turkey) Used as Building Stone for the Restoring Cultural Heritage

Exposure Time Impact on the Geomechanical Characteristics of Sandstone Formation during Horizontal Drilling

Correlation of core and downhole seismic velocities in high-pressure metamorphic rocks: A case study for the COSC-1 borehole, Sweden

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