scholarly journals Role of Cyclic Thermal Shocks on the Physical and Mechanical Responses of White Marble

Machines ◽  
2022 ◽  
Vol 10 (1) ◽  
pp. 58
Author(s):  
Yujie Feng ◽  
Haijian Su ◽  
Yinjiang Nie ◽  
Honghui Zhao
Keyword(s):  
Thermal Shock ◽  
Wave Velocity ◽  
Shear Failure ◽  
P Wave ◽  
Rock Properties ◽  
Compression Tests ◽  
Underground Engineering ◽  
P Wave Velocity ◽  
Thermal Shocks

Marble is a common rock used in many buildings for structural or ornamental purposes and is widely distributed in underground engineering projects. The rocks are exposed to high temperatures when a tunnel fire occurs, and they will be rapidly cooled during the rescue process, which has a great impact on the rock performance and the underground engineering stability. Therefore, the role of cyclic thermal shocks on the physical and mechanical properties of marble specimens was systematically investigated. Different cyclic thermal shock treatments (T = 25, 200, 400, 600, 800 °C; N = 1, 3, 5, 7, 9) were applied to marble specimens and the changes in mass, volume, density and P-wave velocity were recorded in turn. Then, the thermal conductivity, optical microscopy and uniaxial compression tests were carried out. The results showed that both the cyclic thermal shock numbers (N) and the temperature level (T) weaken the rock properties. When the temperature of a thermal shock exceeds 600 °C, the mass loss coefficient and porosity of the marble will increase significantly. The most noticeable change in P-wave velocity occurs between 200 and 400 °C, with a 52.98% attenuation. After three thermal shocks, the cyclic thermal shock numbers have little influence on the uniaxial compressive strength and Young’s modulus of marble specimens. Shear failure is the principal failure mode in marble specimens that have experienced severe thermal damage (high N or T). The optical microscopic pictures are beneficial for illustrating the thermal cracking mechanism of marble specimens after cyclic thermal shocks.

Acoustic signature of fluid substitution in reservoir rocks

2020 ◽  
Author(s):  
Christian David ◽  
Joël Sarout ◽  
Christophe Barnes ◽  
Jérémie Dautriat ◽  
Lucas Pimienta
Keyword(s):  
Wave Velocity ◽  
Water Injection ◽  
P Wave ◽  
Rock Properties ◽  
Fluid Distribution ◽  
Fluid Substitution ◽  
Ultrasonic Monitoring ◽  
Reservoir Rocks ◽  
Water Imbibition ◽  
P Wave Velocity

<p>During the production of hydrocarbon reservoirs, EOR operations, storage of CO2 underground or geothermal fluid exchanges at depth, fluid substitution processes can lead to significant changes in rock properties which can be captured from the variations in seismic waves attributes. In the laboratory, fluid substitution processes can be investigated using ultrasonic monitoring. </p><p>The motivation of our study was to identify the seismic attributes of fluid substitution in reservoir rocks through a direct comparison between the variation in amplitude, velocity, spectral content, energy, and the actual fluid distribution in the rocks. Different arrays of ultrasonic P-wave sensors were used to record at constant time steps the waveforms during fluid substitution experiments. Two different kinds of experiments are presented: (i) water injection experiments in oil-saturated samples under stress in a triaxial setup mimicking EOR operations, (ii) spontaneous water imbibition experiments at room conditions.</p><p>In the water injection tests on a poorly consolidated sandstone saturated with oil and loaded at high deviatoric stresses, water weakening triggers mechanical instabilities leading to the rock failure. The onset of such instabilities can be followed with ultrasonic monitoring either in the passive mode (acoustic emissions recording) or in the active mode (P wave velocity survey).</p><p>In the water imbibition experiments, a methodology based on the analytical signal and instantaneous phase was designed to decompose each waveform into discrete wavelets associated with direct or reflected waves. The energy carried by the wavelets is very sensitive to the fluid substitution process: the coda wavelets are impacted as soon as imbibition starts and can be used as a precursor for remote fluid substitution. It is also shown that the amplitude of the first P-wave arrival is impacted by the upward moving fluid front before the P-wave velocity is. Several scenarios are discussed to explain the decoupling between P wave amplitude and velocity variations during fluid substitution processes.</p>

Studying the correlation of rock properties with P-wave velocity index in dry and saturated conditions

2019 ◽  
Vol 169 ◽  
pp. 49-57 ◽  
Author(s):  
Mohammad Rezaei ◽  
Pouya Koureh Davoodi ◽  
Iraj Najmoddini
Keyword(s):  
Wave Velocity ◽  
P Wave ◽  
Rock Properties ◽  
P Wave Velocity

scholarly journals Experimental Investigation of the Relationship between the P-Wave Velocity and the Mechanical Properties of Damaged Sandstone

2016 ◽  
Vol 2016 ◽  
pp. 1-10 ◽  
Author(s):  
Qi-Le Ding ◽  
Shuai-Bing Song
Keyword(s):  
Mechanical Properties ◽  
High Temperature ◽  
Young’S Modulus ◽  
Wave Velocity ◽  
Young's Modulus ◽  
P Wave ◽  
Rock Properties ◽  
High Temperature Treatment ◽  
P Wave Velocity ◽  
The Relationship

To obtain an improved and more accurate understanding of the relationship between the P-wave velocity and the mechanical properties of damaged sandstone, uniaxial compression tests were performed on sandstone subjected to different high-temperature treatments or freeze-thaw (F-T) cycles. After high-temperature treatment, the tests showed a generally positive relationship between the P-wave velocity and mechanical characteristics, although there were many exceptions. The mechanical properties showed significant differences for a given P-wave velocity. Based on the mechanical tests after the F-T cycles, the mechanical properties and P-wave velocities exhibited different trends. The UCS and Young’s modulus values slightly decreased after 30, 40, and 50 cycles, whereas both an increase and a decrease occurred in the P-wave velocity. The UCS, Young’s modulus, and P-wave velocity represent different macrobehaviors of rock properties. A statistical relationship exists between the P-wave velocity and mechanical properties, such as the UCS and Young’s modulus, but no mechanical relationship exists. Further attention should be given to using the P-wave velocity to estimate and predict the mechanical properties of rock.

scholarly journals On The Low-Frequency Elastic Response of Pierre Shale During Temperature Cycles

2021 ◽  
Author(s):  
Stian Rørheim ◽  
Andreas Bauer ◽  
Rune M Holt
Keyword(s):  
Wave Velocity ◽  
Low Frequency ◽  
P Wave ◽  
Rock Properties ◽  
Fluid Viscosity ◽  
S Wave ◽  
Temperature Cycles ◽  
Wave Velocities ◽  
Young’S Moduli ◽  
P Wave Velocity

Summary The impact of temperature on elastic rock properties is less-studied and thus less-understood than that of pressure and stress. Thermal effects on dispersion are experimentally observed herein from seismic to ultrasonic frequencies: Young’s moduli and Poisson’s ratios plus P- and S-wave velocities are determined by forced-oscillation (FO) from 1 to 144 Hz and by pulse-transmission (PT) at 500 kHz. Despite being the dominant sedimentary rock type, shales receive less experimental attention than sandstones and carbonates. To our knowledge, no other FO studies on shale at above ambient temperatures exist. Temperature fluctuations are enforced by two temperature cycles from 20 via 40 to 60○C and vice versa. Measured rock properties are initially irreversible but become reversible with increasing number of heating and cooling segments. Rock property-sensitivity to temperature is likewise reduced. It is revealed that dispersion shifts towards higher frequencies with increasing temperature (reversible if decreased), Young’s moduli and P-wave velocity moduli and P-wave velocity maxima occur at 40○C for frequencies below 56 Hz, and S-wave velocities remain unchanged with temperature (if the first heating segment is neglected) at seismic frequencies. In comparison, ultrasonic P- and S-wave velocities are found to decrease with increasing temperatures. Behavioural differences between seismic and ultrasonic properties are attributed to decreasing fluid viscosity with temperature. We hypothesize that our ultrasonic recordings coincide with the transition-phase separating the low- and high-frequency regimes while our seismic recordings are within the low-frequency regime.

Multicomponent VP/VS correlation analysis

Geophysics ◽  
1996 ◽  
Vol 61 (4) ◽  
pp. 1137-1149 ◽  
Author(s):  
James E. Gaiser
Keyword(s):  
Correlation Analysis ◽  
Wave Velocity ◽  
Seismic Profile ◽  
P Wave ◽  
Rock Properties ◽  
Wave Reflections ◽  
S Wave ◽  
Long Wavelength ◽  
Amplitude Inversion ◽  
P Wave Velocity

An important step in the simultaneous interpretation or inversion of multicomponent data sets is to quantitatively estimate the ratio of P‐wave velocity to S‐wave velocity [Formula: see text]. In this endeavor, I have developed correlation techniques to determine long‐wavelength components of [Formula: see text] that can lead to more accurate measurements of rock properties and processing parameters. P‐wave reflections are correlated with converted P‐ to S‐wave reflections (or S‐wave reflections) from the same location to determine which events are related to the same subsurface impedance contrasts. Shear waves are transformed (compressed) to P‐wave time via average [Formula: see text] conjugate operators before correlation. Aided by conventional P‐wave velocity information and petrophysical relationships, this technique provides optimal [Formula: see text] estimates in a similar manner that semblance analyses provide stacking velocities. These estimates can be used to transform the entire S‐wave trace to P‐wave time for short‐wavelength amplitude inversion. Also, a target‐oriented correlation analysis quantitatively determines interval [Formula: see text] at a specific horizon or group of horizons. Data from vertical seismic profile (VSP) stacked traces are used to evaluate these techniques. Long‐wavelength average and interval [Formula: see text] estimates obtained from the correlation analyses agree closely with [Formula: see text] results determined from VSP direct‐arrival traveltimes.

Basin-wide empirical rock-physics transform and its application in Campeche Basin

2021 ◽  
Vol 40 (3) ◽  
pp. 178-185
Author(s):  
Yangjun (Kevin) Liu ◽  
Jonathan Hernandez Casado ◽  
Mohamed El-Toukhy ◽  
Shenghong Tai
Keyword(s):  
Pore Pressure ◽  
Wave Velocity ◽  
Effective Stress ◽  
Seismic Data ◽  
Sedimentary Basin ◽  
Rock Physics ◽  
P Wave ◽  
Rock Properties ◽  
Borehole Data ◽  
P Wave Velocity

Rock properties in the subsurface are of major importance for evaluating the petroleum prospectivity of a sedimentary basin. The key rock properties to understand are porosity, density, temperature, effective stress, and pore pressure. These rock properties can be obtained or calculated when borehole data are available. However, borehole data are usually sparse, especially in frontier basins. We propose some simple rock-physics transforms for converting P-wave velocity to other rock properties. We found that these rock-physics transforms are predictive in the east and west sides of Campeche Basin. The proposed rock-physics transforms can be used to obtain laterally varying rock properties based on information derived from seismic data.

scholarly journals Analysis of Effects of Rock Physical Properties Changes from Freeze-Thaw Weathering in Ny-Ålesund Region: Part 1—Experimental Study

2020 ◽  
Vol 10 (5) ◽  
pp. 1707 ◽  
Author(s):  
Keunbo Park ◽  
Kiju Kim ◽  
Kichoel Lee ◽  
Dongwook Kim
Keyword(s):  
Compressive Strength ◽  
Uniaxial Compressive Strength ◽  
Wave Velocity ◽  
Meteorological Data ◽  
P Wave ◽  
Rock Properties ◽  
Shore Hardness ◽  
Freeze Thaw ◽  
Thaw Cycle ◽  
P Wave Velocity

In order to investigate the weathering characteristics of rocks in response to freeze-thaw conditions in northern latitudes, we analysed meteorological data from the Ny-Ålesund region in Norway, and observed changes in the physical and mechanical properties of rocks of dolomite and quartzite. To assess the effects of freeze-thaw weathering on these rock properties, 900 cycles of long-term freeze-thaw tests were conducted for the sampled rocks in two locations. P-wave velocity, absorption, shore hardness, and the uniaxial compressive strength of the sampled rocks were measured at every 150 cycles in order to analyse physical and mechanical mediator variables of freeze-thaw weathering. It was found that an increasing number of freeze-thaw cycle on the sampled rocks decreases uniaxial compressive strength, shore hardness, and P-wave velocity and increases absorption.

Interpretation of AVO anomalies

Geophysics ◽  
2010 ◽  
Vol 75 (5) ◽  
pp. 75A3-75A13 ◽  
Author(s):  
Douglas J. Foster ◽  
Robert G. Keys ◽  
F. David Lane
Keyword(s):  
Wave Velocity ◽  
Seismic Data ◽  
P Wave ◽  
Rock Properties ◽  
Light Hydrocarbons ◽  
S Wave ◽  
Amplitude Variation With Offset ◽  
P Wave Velocity ◽  
Fluid Properties ◽  
Porosity Changes

We investigate the effects of changes in rock and fluid properties on amplitude-variation-with-offset (AVO) responses. In the slope-intercept domain, reflections from wet sands and shales fall on or near a trend that we call the fluid line. Reflections from the top of sands containing gas or light hydrocarbons fall on a trend approximately parallel to the fluid line; reflections from the base of gas sands fall on a parallel trend on the opposing side of the fluid line. The polarity standard of the seismic data dictates whether these reflections from the top of hydrocarbon-bearing sands are below or above the fluid line. Typically, rock properties of sands and shales differ, and therefore reflections from sand/shale interfaces are also displaced from the fluid line. The distance of these trends from the fluid line depends upon the contrast of the ratio of P-wave velocity [Formula: see text] and S-wave velocity [Formula: see text]. This ratio is a function of pore-fluid compressibility and implies that distance from the fluid line increases with increasing compressibility. Reflections from wet sands are closer to the fluid line than hydrocarbon-related reflections. Porosity changes affect acoustic impedance but do not significantly impact the [Formula: see text] contrast. As a result, porosity changes move the AVO response along trends approximately parallel to the fluid line. These observations are useful for interpreting AVO anomalies in terms of fluids, lithology, and porosity.

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