scholarly journals Effect of Mineral Processes and Deformation on the Petrophysical Properties of Soft Rocks during Active Faulting

Minerals ◽  
2020 ◽  
Vol 10 (5) ◽  
pp. 444
Author(s):  
Anita Torabi ◽  
Juan Jiménez-Millán ◽  
Rosario Jiménez-Espinosa ◽  
Francisco Juan García-Tortosa ◽  
Isabel Abad ◽  
...  
Keyword(s):  
Young’S Modulus ◽  
Young's Modulus ◽  
Damage Zone ◽  
Active Faults ◽  
Soft Rock ◽  
Microstructural Characterization ◽  
Rock Properties ◽  
Deformation Bands ◽  
Carbonate Cement ◽  
Granada Basin

We have studied damage zones of two active faults, Baza and Padul faults in Guadix-Baza and Granada basins, respectively, in South Spain. Mineral and microstructural characterization by X-ray diffraction and field emission electron microscopy studies have been combined with structural fieldwork and in situ measurements of rock properties (permeability and Young’s modulus) to find out the relation between deformation behavior, mineral processes, and changes in the soft rock and sediment properties produced by fluid flow during seismic cycles. Our results show that microsealing produced by precipitation of dolomite and aragonite along fractures in the damage zone of Baza Fault reduces the permeability and increases the Young’s modulus. In addition, deformation bands formed in sediments richer in detrital silicates involved cataclasis as deformation mechanism, which hamper permeability of the sediments. In the Granada Basin, the calcarenitic rocks rich in calcite and clays in the damage zone of faults associated to the Padul Fault are characterized by the presence of stylolites without any carbonate cement. On the other hand, marly lithofacies affected by faults are characterized by the presence of disaggregation bands that involve cracking and granular flow, as well as clay smear. The presence of stylolites and deformation bands in these rocks reduces permeability.

scholarly journals On the Effect of CO2 on Seismic and Ultrasonic Properties: A Novel Shale Experiment

Energies ◽  
2021 ◽  
Vol 14 (16) ◽  
pp. 5007
Author(s):  
Stian Rørheim ◽  
Mohammad Hossain Bhuiyan ◽  
Andreas Bauer ◽  
Pierre Rolf Cerasi
Keyword(s):  
Young’S Modulus ◽  
Wave Velocity ◽  
Poisson’S Ratio ◽  
Young's Modulus ◽  
Co2 Storage ◽  
Poisson's Ratio ◽  
Rock Properties ◽  
S Wave ◽  
Velocity Changes ◽  
4D Seismic

Carbon capture and storage (CCS) by geological sequestration comprises a permeable formation (reservoir) for CO2 storage topped by an impermeable formation (caprock). Time-lapse (4D) seismic is used to map CO2 movement in the subsurface: CO2 migration into the caprock might change its properties and thus impact its integrity. Simultaneous forced-oscillation and pulse-transmission measurements are combined to quantify Young’s modulus and Poisson’s ratio as well as P- and S-wave velocity changes in the absence and in the presence of CO2 at constant seismic and ultrasonic frequencies. This combination is the laboratory proxy to 4D seismic because rock properties are monitored over time. It also improves the understanding of frequency-dependent (dispersive) properties needed for comparing in-situ and laboratory measurements. To verify our method, Draupne Shale is monitored during three consecutive fluid exposure phases. This shale appears to be resilient to CO2 exposure as its integrity is neither compromised by notable Young’s modulus and Poisson’s ratio nor P- and S-wave velocity changes. No significant changes in Young’s modulus and Poisson’s ratio seismic dispersion are observed. This absence of notable changes in rock properties is attributed to Draupne being a calcite-poor shale resilient to acidic CO2-bearing brine that may be a suitable candidate for CCS.

Development of Ti-12Mo-8Nb Alloy for Biomedical Application

2017 ◽  
Vol 899 ◽  
pp. 191-194
Author(s):  
Sinara Borborema Gabriel ◽  
Jessica Peixoto da Silva Kassya ◽  
Caroline Miranda Jacinto ◽  
Leizy Pâmela Oliveira dos Santos ◽  
Carlos Angelo Nunes ◽  
...  
Keyword(s):  
Young’S Modulus ◽  
Biomedical Application ◽  
Young's Modulus ◽  
High Vacuum ◽  
High Strength ◽  
Microstructural Characterization ◽  
Β Phase ◽  
Beta Titanium ◽  
Heat Treated ◽  
Alloy Heat

Several beta titanium alloys were developed for biomedical applications due to the combination of low elasticity modulus, high strength, fatigue resistance and good ductility with excellent corrosion resistance. In this regard, a new metastable beta titanium Ti-12Mo-8Nb alloy was developed, as an alternative for the traditional Ti-6Al-4V alloy, with the substitution of vanadium and aluminum for molybdenum and niobium. The objective of this work was to present the microstructural characterization and mechanical properties of the Ti-12Mo-8Nb alloy, heat treated for 1h at 950oC under high vacuum and then water quenched. The microstructure of the alloy was characterized by X-ray diffraction and optical microscopy. Vickers microhardness and nanoindentation were performed for determination of hardness, Young’s modulus and the ratio of hardness to Young’s modulus. The Ti-12Mo-8Nb microstructure consisted of β phase and the values obtained for the ratio of hardness to Young’s modulus were higher than the Ti-6Al-4V alloy.

scholarly journals Stress rotation – impact and interaction of rock stiffness and faults

Solid Earth ◽  
2021 ◽  
Vol 12 (6) ◽  
pp. 1287-1307
Author(s):  
Karsten Reiter
Keyword(s):  
Young’S Modulus ◽  
Poisson’S Ratio ◽  
Young's Modulus ◽  
Active Faults ◽  
Stress Pattern ◽  
Poisson's Ratio ◽  
Upper Crust ◽  
Low Friction ◽  
Stress Rotation ◽  
Order Stress

Abstract. It has been assumed that the orientation of the maximum horizontal compressive stress (SHmax) in the upper crust is governed on a regional scale by the same forces that drive plate motion. However, several regions are identified where stress orientation deviates from the expected orientation due to plate boundary forces (first-order stress sources), or the plate wide pattern. In some of these regions, a gradual rotation of the SHmax orientation has been observed. Several second- and third-order stress sources have been identified in the past, which may explain stress rotation in the upper crust. For example, lateral heterogeneities in the crust, such as density and petrophysical properties, and discontinuities, such as faults, are identified as potential candidates to cause lateral stress rotations. To investigate several of these candidates, generic geomechanical numerical models are set up with up to five different units, oriented by an angle of 60∘ to the direction of shortening. These units have variable (elastic) material properties, such as Young's modulus, Poisson's ratio and density. In addition, the units can be separated by contact surfaces that allow them to slide along these vertical faults, depending on a chosen coefficient of friction. The model results indicate that a density contrast or the variation of Poisson's ratio alone hardly rotates the horizontal stress (≦17∘). Conversely, a contrast of Young's modulus allows significant stress rotations of up to 78∘, even beyond the vicinity of the material transition (>10 km). Stress rotation clearly decreases for the same stiffness contrast, when the units are separated by low-friction discontinuities (only 19∘ in contrast to 78∘). Low-friction discontinuities in homogeneous models do not change the stress pattern at all away from the fault (>10 km); the stress pattern is nearly identical to a model without any active faults. This indicates that material contrasts are capable of producing significant stress rotation for larger areas in the crust. Active faults that separate such material contrasts have the opposite effect – they tend to compensate for stress rotations.

Application of nanoindentation for uncertainty assessment of elastic properties in mudrocks from micro- to well-log scales

Geophysics ◽  
2017 ◽  
Vol 82 (6) ◽  
pp. D327-D339 ◽  
Author(s):  
Clotilde Chen Valdes ◽  
Zoya Heidari
Keyword(s):  
Young’S Modulus ◽  
Clay Minerals ◽  
Elastic Properties ◽  
Young's Modulus ◽  
Soft Rock ◽  
Elastic Stiffness ◽  
Mechanical Tests ◽  
Well Log ◽  
Eagle Ford ◽  
Effective Elastic Properties

Uncertainty in estimates of elastic properties of soft mudrock components, such as clay minerals and kerogen, can influence well-log-based evaluation of effective elastic properties in organic-rich mudrocks. Existing methods, such as effective medium models for well-log-based assessment of elastic properties, assume a constant stiffness and an idealized shape for rock components. However, these characteristics might vary depending on the distribution and size of that particular component, as well as its adjacent components. Furthermore, there is a significant uncertainty in elastic properties of kerogen in the case of organic-rich mudrocks. The uncertainty associated with the aforementioned parameters on effective elastic properties of rocks has not been investigated in existing publications. In this paper, we quantified the variability in elastic properties of individual mudrock components caused by their spatial distribution, size, and rock fabric at the microscale and their impacts on well-log-based evaluation of effective elastic properties. We performed nanoindentation mechanical tests on samples from the Haynesville and the lower Eagle Ford Formations, to measure Young’s modulus and hardness at targeted locations. Then, we quantified the variability of Young’s modulus in the microscale and its impact on effective elastic properties at the micro- and well-log scales. Results reveal significant uncertainties in measurements of elastic properties of soft rock components, associated with their location and size. Young’s moduli of individual clay components are higher when located adjacent to stiff rock components, such as large quartz and calcite grains. Results reveal that 25% and 12% uncertainties in measured elastic properties of clay minerals affect well-log-based estimates of effective elastic stiffness coefficients up to 29% and 11% in the Haynesville and the lower Eagle Ford Formations, respectively. These uncertainties can be more significant in cases with a higher concentration of clay minerals and kerogen.

Reduction In Young's Modulus Of Aluminum Foams Due To Cell Wall Curvature And Corrugation

1998 ◽  
Vol 521 ◽  
Author(s):  
W. Sanders ◽  
L. J. Gibson
Keyword(s):  
Compressive Strength ◽  
Cell Wall ◽  
Young’S Modulus ◽  
Cell Walls ◽  
Young's Modulus ◽  
Cell Structure ◽  
Microstructural Characterization ◽  
Aluminum Foams ◽  
Element Analysis ◽  
Simple Bounds

ABSTRACTMeasurements of the Young's modulus and compressive strength of several closedcell aluminum foams indicate that they are lower than expected from models for foam behaviour. Microstructural characterization has revealed that there are a number of defects in the cell structure which may contribute to the reduction in mechanical properties. These include: cell wall curvature, cell wall corrugations, density variations and non-equiaxed cell shape. Finite element analysis of a closed-cell tetrakaidecahedral unit cell with idealized curved or corrugated cell walls indicates that these two types of defects can reduce the Young's modulus and compressive strength by up to 70%. In this paper we report the results of measurements of the curvature of the cell walls and of the amplitude and frequency of corrugations in the cell walls and use simple bounds to estimate the reduction in modulus that they are responsible for.

scholarly journals Stress rotation – The impact and interaction of rock stiffness and faults

2020 ◽  
Author(s):  
Karsten Reiter
Keyword(s):  
Young’S Modulus ◽  
Young's Modulus ◽  
Active Faults ◽  
Horizontal Stress ◽  
Stress Pattern ◽  
Upper Crust ◽  
Low Friction ◽  
Stress Rotation ◽  
Stress Orientation ◽  
Order Stress

Abstract. It has been assumed, that the maximum compressive horizontal stress (SHmax) orientation in the upper crust is governed on a regional scale by the same forces that drive plate motion. However, several regions are identified, where stress orientation deviates from the expected orientation due to plate boundary forces (first order stress sources), or the plate wide pattern. In some of this regions a gradual rotation of the SHmax orientation has been observed. Several second and third order stress sources have been identified, which may explain stress rotation in the upper crust. For example lateral heterogeneities in the crust, such as density, petrophysical or petrothermal properties and discontinuities, like faults are identified as potential candidates to cause lateral stress rotations. To investigate several of the candidates, generic geomechanical numerical models are utilized. These models consist of up to five different units, oriented by an angle of 60° to the direction of contraction. These units have variable elastic material properties, such as Young's modulus, Poisson ratio and density. Furthermore, the units can be separated by contact surfaces that allow them so slide along these faults, depending on a selected coefficient of friction. The model results indicate, that a density contrast or the variation of the Poisson's ratio alone sparsely rotates the horizontal stress orientation (≦ 17°). Conversely, a contrast of the Young's modulus allows significant stress rotations in the order of up to 78°; not only areas in the vicinity of the material transition are affected by that stress rotation. Stress rotation clearly decreases for the same stiffness contrast, when the units are separated by low friction discontinuities (19°). Low friction discontinuities in homogeneous models do not change the stress pattern at all, away from the fault; the stress pattern is nearly identical to a model without any active faults. This indicates that material contrasts are capable of producing significant stress rotation for larger areas in the crust. Active faults that separates such material contrasts have the opposite effect, they rather compensate stress rotations.

scholarly journals Uncertainty Analysis of Factors Influencing Stimulated Fracture Volume in Layered Formation

Energies ◽  
2019 ◽  
Vol 12 (23) ◽  
pp. 4444 ◽  
Author(s):  
Jingxuan Zhang ◽  
Xiangjun Liu ◽  
Xiaochen Wei ◽  
Lixi Liang ◽  
Jian Xiong ◽  
...  
Keyword(s):  
Young’S Modulus ◽  
Young's Modulus ◽  
Three Dimensional ◽  
Prediction Equation ◽  
Injection Rate ◽  
Rock Properties ◽  
Three Dimensional Model ◽  
Stimulated Reservoir Volume ◽  
Reservoir Volume ◽  
Layered Formation

Hydraulic fracture dimension is one of the key parameters affecting stimulated porous media. In actual fracturing, plentiful uncertain parameters increase the difficulty of fracture dimension prediction, resulting in the difficulty in the monitoring of reservoir productivity. In this paper, we established a three-dimensional model to analyze the key factors on the stimulated reservoir volume (SRV), with the response surface method (RSM). Considering the rock properties and fracturing parameters, we established a multivariate quadratic prediction equation. Simulation results show that the interactions of injection rate (Q), Young’s modulus (E) and permeability coefficient (K), and Poisson’s ratio (μ) play a relatively significant role on SRV. The reservoir with a high Young’s modulus typically generates high pressure, leading to longer fractures and larger SRV. SRV reaches the maximum value when E1 and E2 are high. SRV is negatively correlated with K1. Moreover, maintaining a high injection rate in this layered formation with high E1 and E2, relatively low K1, and μ1 at about 0.25 would be beneficial to form a larger SRV. These results offer new perceptions on the optimization of SRV, helping to improve the productivity in hydraulic fracturing.

scholarly journals Discrepancy between measured dynamic poroelastic parameters and predicted values from Wyllie’s equation for water-saturated Istebna sandstone

2021 ◽  
Author(s):  
Dariusz Knez ◽  
Herimitsinjo Rajaoalison
Keyword(s):  
Young’S Modulus ◽  
Poisson’S Ratio ◽  
Young's Modulus ◽  
Laboratory Data ◽  
Confining Pressure ◽  
P Wave ◽  
Poisson's Ratio ◽  
Rock Properties ◽  
Biot’S Coefficient ◽  
Water Saturated

AbstractThe drilling-related geomechanics requires a better understanding of the encountered formation properties such as poroelastic parameters. This paper shows set of laboratory results of the dynamic Young’s modulus, Poisson’s ratio, and Biot’s coefficient for dry and water-saturated Istebna sandstone samples under a series of confining pressure conditions at two different temperatures. The predicted results from Wyllie’s equation were compared to the measured ones in order to show the effect of saturation on the rock weakening. A negative correlation has been identified between Poisson’s ratio, Biot’s coefficient and confining pressure, while a positive correlation between confining pressure and Young’s modulus. The predicted dynamic poroelastic rock properties using the P-wave value from Wyllie’s equation are different from measured ones. It shows the important influence of water saturation on rock strength, which is confirmed by unconfined compressive strength measurement. Linear equations have been fitted for the laboratory data and are useful for the analysis of coupled stress and pore pressure effects in geomechanical problems. Such results are useful for many drilling applications especially in evaluation of such cases as wellbore instability and many other drilling problems.

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.

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