scholarly journals Characterization of Microschist Rocks under High Temperature at Najran Area of Saudi Arabia

Energies ◽  
2021 ◽  
Vol 14 (22) ◽  
pp. 7612
Author(s):  
Haitham M. Ahmed ◽  
Hussin A. M. Ahmed ◽  
Sefiu O. Adewuyi
Keyword(s):  
Wave Velocity ◽  
High Temperatures ◽  
Physical And Mechanical Properties ◽  
P Wave ◽  
Structural Deformation ◽  
Dry Density ◽  
Rock Types ◽  
P Wave Velocity ◽  
Microscopic Studies

Rocks’ physical, mechanical, and mineralogical properties are essential in the design process of underground applications. To understand changes in these rocks’ properties at high temperatures, numerous studies have been conducted on several rock types, with little being known about microschist rock. This paper presents experimental study on the physical (e.g., density and P-wave velocity), mechanical (uniaxial compressive strength (UCS)), and microstructural behavior of microschist rock at room temperature (22 °C) and at high temperatures, i.e., 400, 600, and 800 °C. The results indicated that as the temperature increases, the microschist’s color changed, and dry density decreased by 0.97% at 800 °C. Additionally, the average P-wave velocity of microschist decreased by 4.14, 7.07, and 34.23%, at 400, 600, and 800 °C, respectively. Similarly, at these temperatures, the UCS of the microschist decreased by 34.4, 56.9, and 80.1%, respectively. Further findings from microscopic studies reveal that the observed changes in physical and mechanical properties were due to the structural deformation of the microschist at high temperatures.

Assessment of engineering behaviour of an intensely weathered swelling mudstone under full range of seasonal variation and the relationships among measured parameters

2018 ◽  
Vol 55 (12) ◽  
pp. 1837-1849 ◽  
Author(s):  
Zhixiong Zeng ◽  
Lingwei Kong ◽  
Min Wang ◽  
Hossain Md. Sayem
Keyword(s):  
Electrical Resistivity ◽  
Shear Strength ◽  
Wave Velocity ◽  
Full Range ◽  
Aggregate Size ◽  
Physical And Mechanical Properties ◽  
Inverse Correlation ◽  
Strong Relationship ◽  
P Wave ◽  
P Wave Velocity

An experimental study was conducted to investigate the physical and mechanical properties of an intensely weathered mudstone from Northeast China after wetting–drying (W–D), freezing–thawing (F–T), and wetting–drying–freezing–thawing (W–D–F–T) cycles. These cyclic climatic processes have significant effects on the volume, microstructure, stress–strain behaviour, shear strength, electrical resistivity, and P-wave velocity of the samples. The variation in electrical resistivity exhibits an inverse correlation with the volume change, and a strong relationship can be observed between the electrical resistivity and porosity. The cohesion decreases with increasing number of cycles, while the internal friction angle slightly increases; these relationships can be caused by the presence of cracks and large voids and by the increase in the aggregate size and density during the drying and freezing processes, respectively. Moreover, the W–D–F–T cycles have a greater influence on the shear strength than do either the W–D or F–T cycles. This phenomenon is similar to that observed in the P-wave velocity, and the relationships between the shear strength parameters and P-wave velocity are also explored. This study provides nondestructive methods of predicting the deformation and shear strength of mudstones in seasonally frozen regions.

Petrophysical, mineralogical, and P-wave velocity characterization of Albian carbonates from Campos Basin, Brazil

2013 ◽  
Author(s):  
Nathaly Archilha ◽  
Roseane Missàgia ◽  
Marco de Ceia ◽  
Irineu Lima Neto ◽  
Luan de Castro ◽  
...  
Keyword(s):  
Wave Velocity ◽  
P Wave ◽  
Campos Basin ◽  
P Wave Velocity

Laboratory characterization of coal P-wave velocity variation during adsorption of methane under tri-axial stress condition

Fuel ◽  
2020 ◽  
Vol 272 ◽  
pp. 117698
Author(s):  
Shuangjiang Zhu ◽  
Fubao Zhou ◽  
Jianhong Kang ◽  
Youpai Wang ◽  
Haijian Li ◽  
...  
Keyword(s):  
Wave Velocity ◽  
Stress Condition ◽  
Axial Stress ◽  
P Wave ◽  
Velocity Variation ◽  
Laboratory Characterization ◽  
P Wave Velocity ◽  
Adsorption Of Methane

scholarly journals Quantitative seismic characterization of CO2 at the Sleipner storage site, North Sea

2017 ◽  
Vol 5 (4) ◽  
pp. SS23-SS42 ◽  
Author(s):  
Bastien Dupuy ◽  
Anouar Romdhane ◽  
Peder Eliasson ◽  
Etor Querendez ◽  
Hong Yan ◽  
...  
Keyword(s):  
High Resolution ◽  
Wave Velocity ◽  
Rock Physics ◽  
Joint Estimation ◽  
P Wave ◽  
Storage Site ◽  
Seismic Waveform ◽  
P Wave Velocity ◽  
Seismic Characterization

Reliable quantification of carbon dioxide ([Formula: see text]) properties and saturation is crucial in the monitoring of [Formula: see text] underground storage projects. We have focused on quantitative seismic characterization of [Formula: see text] at the Sleipner storage pilot site. We evaluate a methodology combining high-resolution seismic waveform tomography, with uncertainty quantification and rock physics inversion. We use full-waveform inversion (FWI) to provide high-resolution estimates of P-wave velocity [Formula: see text] and perform an evaluation of the reliability of the derived model based on posterior covariance matrix analysis. To get realistic estimates of [Formula: see text] saturation, we implement advanced rock physics models taking into account effective fluid phase theory and patchy saturation. We determine through sensitivity tests that the estimation of [Formula: see text] saturation is possible even when using only the P-wave velocity as input. After a characterization of rock frame properties based on log data prior to the [Formula: see text] injection at Sleipner, we apply our two-step methodology. The FWI result provides clear indications of the injected [Formula: see text] plume being observed as low-velocity zones corresponding to thin [Formula: see text] filled layers. Several tests, varying the rock physics model and [Formula: see text] properties, are then performed to estimate [Formula: see text] saturation. The results suggest saturations reaching 30%–35% in the thin sand layers and up to 75% when patchy mixing is considered. We have carried out a joint estimation of saturation with distribution type and, even if the inversion is not well-constrained due to limited input data, we conclude that the [Formula: see text] has an intermediate pattern between uniform and patchy mixing, which leads to saturation levels of approximately [Formula: see text]. It is worth noting that the 2D section used in this work is located 533 m east of the injection point. We also conclude that the joint estimation of [Formula: see text] properties with saturation is not crucial and consequently that knowing the pressure and temperature state of the reservoir does not prevent reliable estimation of [Formula: see text] saturation.

scholarly journals Combined controls of sedimentology and diagenesis on seismic properties in lacustrine and palustrine carbonates (Upper Miocene, Samos Island, Greece)

2019 ◽  
Vol 219 (2) ◽  
pp. 1300-1315 ◽  
Author(s):  
C Bailly ◽  
M Adelinet ◽  
Y Hamon ◽  
J Fortin
Keyword(s):  
Physical Properties ◽  
Wave Velocity ◽  
Mineralogical Composition ◽  
Sedimentary Facies ◽  
P Wave ◽  
Seismic Properties ◽  
Diagenetic Processes ◽  
P Wave Velocity ◽  
Seismic Reflectors

SUMMARY For the subsurface characterization of carbonates, linking physical properties (e.g. porosity and seismic reflectors) with their geological significance (e.g. sedimentary facies and diagenesis) is of primary importance. To address this issue, we study the lacustrine and palustrine carbonates on Samos Island through a geological and geophysical characterization of a sedimentary succession. The microstructures of the samples are described, and the samples’ physical properties are measured (porosity, P-wave velocity and density). The results show that the identification of only the primary (i.e. sedimentary) microstructure is not sufficient for explaining the huge variations in porosity and P-wave velocity. Hence, we highlight two early diagenetic processes that strongly impact the microstructures and control the physical properties: (i) neomorphism occludes porosity and increases the P-wave velocity of mud- and grain-supported microstructures, which implies a mineralogical stabilization of the grains; (ii) conversely, the dissolution process creates porosity and decreases the P-wave velocity of grain-supported microstructures if the mineralogical composition of the grains is not previously stabilized. These two diagenetic processes thus depend on the primary microstructures and mineralogy of the sediments. This work aims to explain the variations in porosity and P-wave velocity for each defined primary microstructure. A 1-D seismogram is then built to highlight seismic reflectors with a metre-scale resolution. These reflectors are associated with several geological contrasts. Hard kicks (positive amplitude reflectors) match well with exposure surfaces related to palaeosols. They correspond to contrasts between non-modified primary microstructures and highly neomorphosed microstructures. Conversely, soft kicks (negative amplitude reflectors) are linked with diagenetic contrasts (e.g. neomorphosed microstructures versus non-modified primary microstructures) and sedimentary contrasts that can be overprinted by diagenesis (e.g. neomorphosed mud-supported microstructures versus dissolved grain-supported microstructures). This study highlights that high-resolution seismic reflectors of lacustrine and palustrine carbonates are strongly related to the spatial contrasts of primary microstructures overprinted by early diagenesis.

scholarly journals Geomechanical characterization of mud volcanoes using P-wave velocity datasets

2017 ◽  
Vol 458 (1) ◽  
pp. 273-292 ◽  
Author(s):  
Rashad Gulmammadov ◽  
Stephen Covey-Crump ◽  
Mads Huuse
Keyword(s):  
Wave Velocity ◽  
P Wave ◽  
Mud Volcanoes ◽  
P Wave Velocity ◽  
Geomechanical Characterization
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