Experimental Investigation on Brazilian Tensile Strength of Organic-Rich Gas Shale

SPE Journal ◽  
2016 ◽  
Vol 22 (01) ◽  
pp. 148-161 ◽  
Author(s):  
Hui Li ◽  
Bitao Lai ◽  
Hui-Hai Liu ◽  
Jilin Zhang ◽  
Daniel Georgi
Keyword(s):  
Tensile Strength ◽  
Water Content ◽  
Scale Effects ◽  
Transversely Isotropic ◽  
Fracture Initiation ◽  
Bedding Plane ◽  
Organic Content ◽  
Eagle Ford ◽  
X Ray ◽  
Mancos Shale

Summary Tensile strength is a critical parameter for hydraulic fracturing, predicting fracture initiation and propagation in reservoirs, especially in shale reservoirs with complex natural fractures and fissures. The tensile strength of conventional rocks, such as sandstone and limestone, has been well-studied and -documented. There are many studies of the tensile strength of laminated shale, which focus on scale effects, loading direction, and temperature effects; however, the studies on effects of mineralogy and the water content on tensile strength of organic-rich shales are very limited. The objectives of this paper are to (1) critically review the key parameters that affect the tensile strength of shale and 2) experimentally examine the effects of water content, mineralogy, and lamination on tensile strength. To do so, a rigorous workflow is followed: 1) Each 1-in.-long shale sample is cut into two subsamples, A and B, of similar length; (2) X-ray computed-tomography (CT) scan is performed to diagnose pre-existing cracks and defects inside the core plugs; (3) nuclear magnetic resonance (NMR) is then used to measure the air dry samples’ water content; (4) Sample A is placed on a load frame to measure the tensile strength; (5) Sample B is vacuumed and then saturated; (6) NMR is used to measure the water content after saturation; (7) tensile strength of the saturated Sample B is measured; and (8) after the sample fails, the pieces are used for X-ray diffraction (XRD), scanning electron microscopy (SEM), and pyrolysis to estimate the mineralogy and total organic content (TOC). A total of 70 Mancos and 48 Eagle Ford shale samples have been tested. The experimental results show that (1) bedding plane/lamination has a significant effect on Eagle Ford tensile strength, but no pronounced impact is observed for the Mancos shale; (2) the imbibed water significantly reduces the tensile strength by 4.4 to 51.7% as water content increases from 4.45 to 11.7%; (3) pre-existing detectable microfractures can significantly reduce the tensile strength by up to 66%; (4) Eagle Ford exhibits typical brittle hard-rock failure configuration, with primary fractures and secondary fractures being observed, whereas for the Mancos shale, only primary fractures are observed; (5) acoustic velocity-test results confirm that Eagle Ford is mechanically transversely isotropic, and Mancos is likely mechanically isotropic.

A crack-induced stress approach to describe the tensile strength of transversely isotropic rocks

2002 ◽  
Vol 39 (1) ◽  
pp. 1-13 ◽  
Author(s):  
Li Li ◽  
Michel Aubertin
Keyword(s):  
Tensile Strength ◽  
Transverse Isotropy ◽  
Local Stress ◽  
Transversely Isotropic ◽  
Bedding Plane ◽  
Tensile Failure ◽  
Induced Stress ◽  
Anisotropic Rocks ◽  
Indirect Tensile ◽  
Boundary Equations

Rocks are generally more or less anisotropic, depending on their structure at the scale of interest. In engineering applications, the magnitude of such anisotropy must often be determined for compressive as well as tensile loading conditions. In this paper, the authors present the results of an investigation on tensile failure of transversely isotropic rocks, based on Inglis' analytical solution for the stress at the boundary of an elliptical flaw. The strength of transversely isotropic rocks is assumed to be controlled by the maximum tensile local stress along the crack boundary. Equations are developed and compared with tensile test data taken from the literature. The results show that the proposed formulations represent well the direct and indirect tensile strength of anisotropic rocks as a function of bedding plane orientation. It is also shown that the proposed physical model correlates well with the results obtained from more empirical formulations.Key words: rock mechanics, anisotropy, transverse isotropy, tensile strength, Brazilian test, crack.

scholarly journals Experimental Investigation on the Tensile Strength of Coal: Consideration of the Specimen Size and Water Content

Energies ◽  
2020 ◽  
Vol 13 (24) ◽  
pp. 6585
Author(s):  
Honghua Song ◽  
Yixin Zhao ◽  
Yaodong Jiang ◽  
Weisheng Du
Keyword(s):  
Tensile Strength ◽  
Water Content ◽  
Immersion Time ◽  
Scale Effects ◽  
Fractal Theory ◽  
Failure Process ◽  
Specimen Size ◽  
Tensile Failure ◽  
Microscopic Features ◽  
Water Contents

We experimentally and theoretically explored the microstructure-related effects of water and specimen size on the tensile strength of coal. Cylindrical coal specimens with different sizes (diameters of 25, 38, and 50 mm) and water contents (immersion time lengths: 0, 4, and 7 days) were processed. The microscopic features and mineral compositions of the coal samples were imaged and characterized via scanning electron microscopy (SEM) and X-ray diffraction (XRD). The physicochemical effects of water on the microstructures and coal matrices were investigated by acoustic emission (AE) and fractal theory. In this research, the tensile strength was found to be reduced in larger specimens, which can be explained by an exponential correlation. Water enhances the scale effect on the tensile strength of coal, although the water content decreases in larger specimens. Meanwhile, greater reductions in tensile strength were observed under the coupled effects of the water and specimen size. Based on the AE variation and fractal feature analysis, water was considered to mainly plays roles in dissolving clay minerals, softening the coal matrix, and lubricating cracks during the tensile failure of coal. In addition, the cumulative AE counts and absolute AE energy values decreased with the water content and increased with the specimen size. Similar variations were also observed in the fractal dimension, indicating the intensification of the AE activity concentration around the peak strength area in specimens with greater water contents, as well as a concentration reduction in larger specimen sizes with different water contents. The percentage of tensile failure increased in the diameter range of 25–38 mm and decreased in the range of 38–50 mm. Water increases the proportion of tensile strength generated during the tensile failure process, and this effects increases with the immersion time. Thus, consideration should be given to the combined water and scale effects when extrapolating lab-investigation results to water-related engineering issues in coal mines.

Phase Transformations in Ti-7w/oMo-3w/oMe Alloy

1974 ◽  
Vol 32 ◽  
pp. 514-515
Author(s):  
S. Fujishiro
Keyword(s):  
Electron Microscopy ◽  
Mechanical Properties ◽  
Transmission Electron Microscopy ◽  
Tensile Strength ◽  
Mechanical Processing ◽  
Ray Method ◽  
X Ray ◽  
Transmission Electron ◽  
Water Quench ◽  
Alpha Beta

The mechanical properties of three titanium alloys (Ti-7Mo-3Al, Ti-7Mo- 3Cu and Ti-7Mo-3Ta) were evaluated as function of: 1) Solutionizing in the beta field and aging, 2) Thermal Mechanical Processing in the beta field and aging, 3) Solutionizing in the alpha + beta field and aging. The samples were isothermally aged in the temperature range 300° to 700*C for 4 to 24 hours, followed by a water quench. Transmission electron microscopy and X-ray method were used to identify the phase formed. All three alloys solutionized at 1050°C (beta field) transformed to martensitic alpha (alpha prime) upon being water quenched. Despite this heavily strained alpha prime, which is characterized by microtwins the tensile strength of the as-quenched alloys is relatively low and the elongation is as high as 30%.

SIFAT FISIK KAYU LAPIS BERBAHAN BAKU KAYU AKASIA (Acacia mangium Willd) DAN KELAMPAYAN (Anthocephalu spp)

2011 ◽  
Vol 3 (2) ◽  
pp. 1 ◽  
Author(s):  
Effendi Arsad
Keyword(s):  
Tensile Strength ◽  
Water Content ◽  
Acacia Mangium ◽  
Spreading Rate ◽  
Wood Material

The utilization of acacia and kelampayan wood as  plywood materials  were done. There are two kinds of treatments with two cores samples.  Wood core with thickness 2 mm and 3 mm with the spreading rate of adhesive  150 gr/m2, 200 gr/m2 and 250 gr/m2.   Resuls showed  that the  water content  of plywood  are 9,01% - 14,29%  for acacia and 9,17% - 10,58%   for kelampayan wood material.  The density of the plywood are 0,62 gr/cm3 – 0,73 gr/cm3  for acacia and 0,44 gr/cm3 – 0,57 gr/cm3.  for kelampayan wood material.  The tensile  strength of plywood are tensile strength of  plywood  are 9,49 kg/cm2 – 14,73 kg/cm2  for acacia and 8,61 kg/cm2 – 12,58 kg/cm2   for kelampayan wood material.Keywords: acacia, kelampayan,  the spreading rate of adhesive,  physics       characteristic,  plywood

scholarly journals Multidimensional Ln-Aminophthalate Photoluminescent Coordination Polymers

Materials ◽  
2021 ◽  
Vol 14 (7) ◽  
pp. 1786
Author(s):  
Carla Queirós ◽  
Chen Sun ◽  
Ana M. G. Silva ◽  
Baltazar de Castro ◽  
Juan Cabanillas-Gonzalez ◽  
...  
Keyword(s):  
Water Content ◽  
Coordination Polymers ◽  
Metal Ion ◽  
Low Cost ◽  
Microwave Assisted Synthesis ◽  
X Ray Diffraction ◽  
X Ray ◽  
Wide Range ◽  
Ft Ir ◽  
Ft Ir Spectroscopy

The development of straightforward reproducible methods for the preparation of new photoluminescent coordination polymers (CPs) is an important goal in luminescence and chemical sensing fields. Isophthalic acid derivatives have been reported for a wide range of applications, and in addition to their relatively low cost, have encouraged its use in the preparation of novel lanthanide-based coordination polymers (LnCPs). Considering that the photoluminescent properties of these CPs are highly dependent on the existence of water molecules in the crystal structure, our research efforts are now focused on the preparation of CP with the lowest water content possible, while considering a green chemistry approach. One- and two-dimensional (1D and 2D) LnCPs were prepared from 5-aminoisophthalic acid and Sm3+/Tb3+ using hydrothermal and/or microwave-assisted synthesis. The unprecedented LnCPs were characterized by single-crystal X-ray diffraction (SCRXD), powder X-ray diffraction (PXRD), Fourier transform infrared (FT-IR) spectroscopy and scanning electron microscopy (SEM), and their photoluminescence (PL) properties were studied in the solid state, at room temperature, using the CPs as powders and encapsulated in poly(methyl methacrylate (PMMA) films, envisaging the potential preparation of devices for sensing. The materials revealed interesting PL properties that depend on the dimensionality, metal ion, co-ligand used and water content.

Characteristic properties of AlTiN and TiN coated HSS materials

2015 ◽  
Vol 67 (2) ◽  
pp. 172-180 ◽  
Author(s):  
Mumin Sahin ◽  
Cenk Misirli ◽  
Dervis Özkan
Keyword(s):  
Surface Roughness ◽  
Tensile Strength ◽  
High Speed ◽  
Cutting Tools ◽  
High Speed Steel ◽  
Wear Properties ◽  
Content Type ◽  
X Ray ◽  
Number Of Cycles ◽  
Future Work

Purpose – The purpose of this paper is to examine mechanical and metallurgical properties of AlTiN- and TiN-coates high-speed steel (HSS) materials in detail. Design/methodology/approach – In this study, HSS steel parts have been processed through machining and have been coated with AlTiN and TiN on physical vapour deposition workbench at approximately 6,500°C for 4 hours. Tensile strength, fatigue strength, hardness tests for AlTiN- and TiN-coated HSS samples have been performed; moreover, energy dispersive X-ray spectroscopy and X-ray diffraction analysis and microstructure analysis have been made by scanning electron microscopy. The obtained results have been compared with uncoated HSS components. Findings – It was found that tensile strength of TiAlN- and TiN-coated HSS parts is higher than that of uncoated HSS parts. Highest tensile strength has been obtained from TiN-coated HSS parts. Number of cycles for failure of TiAlN- and TiN-coated HSS parts is higher than that for HSS parts. Particularly TiN-coated HSS parts have the most valuable fatigue results. However, surface roughness of fatigue samples may cause notch effect. For this reason, surface roughness of coated HSS parts is compared with that of uncoated ones. While the average surface roughness (Ra) of the uncoated samples was in the range of 0.40 μm, that of the AlTiN- and TiN-coated samples was in the range of 0.60 and 0.80 μm, respectively. Research limitations/implications – It would be interesting to search different coatings for cutting tools. It could be the good idea for future work to concentrate on wear properties of tool materials. Practical implications – The detailed mechanical and metallurgical results can be used to assess the AlTiN and TiN coating applications in HSS materials. Originality/value – This paper provides information on mechanical and metallurgical behaviour of AlTiN- and TiN-coated HSS materials and offers practical help for researchers and scientists working in the coating area.

scholarly journals Reply [to “Comment on ‘Dual-energy synchrotron X ray measurements of rapid soil density and water content changes in swelling soils during infiltration’ by Patricia Garnier et al.”]

1999 ◽  
Vol 35 (11) ◽  
pp. 3589-3590 ◽  
Author(s):  
Patricia Garnier ◽  
Rafael Angulo-Jaramillo ◽  
David A. DiCarlo ◽  
Tim W. J. Bauters ◽  
Christophe J. G. Darnault ◽  
...  
Keyword(s):  
Water Content ◽  
Dual Energy ◽  
Soil Density ◽  
X Ray ◽  
Swelling Soils

scholarly journals Parameterization of elastic stress sensitivity in shales

Geophysics ◽  
2011 ◽  
Vol 76 (3) ◽  
pp. WA147-WA155 ◽  
Author(s):  
Marina Pervukhina ◽  
Boris Gurevich ◽  
Pavel Golodoniuc ◽  
David N. Dewhurst
Keyword(s):  
Elastic Properties ◽  
Anisotropy Parameter ◽  
Transversely Isotropic ◽  
Bedding Plane ◽  
Stress Sensitivity ◽  
Crack Orientation ◽  
Fluid Identification ◽  
Orientation Anisotropy ◽  
Characteristic Pressure ◽  
Stress Dependency

Stress dependency and anisotropy of dynamic elastic properties of shales is important for a number of geophysical applications, including seismic interpretation, fluid identification, and 4D seismic monitoring. Using Sayers-Kachanov formalism, we developed a new model for transversely isotropic (TI) media that describes stress sensitivity behavior of all five elastic coefficients using four physically meaningful parameters. The model is used to parameterize elastic properties of about 20 shales obtained from laboratory measurements and the literature. The four fitting parameters, namely, specific tangential compliance of a single crack, ratio of normal to tangential compliances, characteristic pressure, and crack orientation anisotropy parameter, show moderate to good correlations with the depth from which the shale was extracted. With increasing depth, the tangential compliance exponentially decreases. The crack orientation anisotropy parameter broadly increases with depth for most of the shales, indicating that cracks are getting more aligned in the bedding plane. The ratio of normal to shear compliance and characteristic pressure decreases with depth to 2500 m and then increases below this to 3600 m. The suggested model allows us to evaluate the stress dependency of all five elastic compliances of a TI medium, even if only some of them are known. This may allow the reconstruction of the stress dependency of all five elastic compliances of a shale from log data, for example.

Structure of Microphase-Separated Silica/Siloxane Molecular Composites

1989 ◽  
Vol 171 ◽  
Author(s):  
Dale W. Schaefer ◽  
James E. Mark ◽  
David Mccarthy ◽  
Li Jian ◽  
C. -C. Sun ◽  
...  
Keyword(s):  
Phase Separation ◽  
Kinetic Studies ◽  
Organic Content ◽  
Small Particles ◽  
X Ray ◽  
Filled Elastomers ◽  
Polymeric Networks ◽  
Large Particles ◽  
Molecular Composites

ABSTRACTThe structure of several classes of silica/siloxane molecular composites is investigated using small-angle x-ray and neutron scattering. These filled elastomers can be prepared through different synthethic protocols leading to a range of fillers including particulates with both rough and smooth surfaces, particulates with dispersed interfaces, and polymeric networks. We also find examples of bicontinuous filler phases that we attribute to phase separation via spinodal decomposition. In-situ kinetic studies of particulate fillers show that the precipitate does not develop by conventional nucleation-and-growth. We see no evidence of growth by ripening whereby large particles grow by consumption of small particles. Rather, there appears to be a limiting size set by the elastomer network itself. Phase separation develops by continuous nucleation of particles and subsequent growth to the limiting size. We also briefly report studies of polymer-toughened glasses. In this case, we find no obvious correlation between organic content and structure.

Fabrication and Research of Electroless Nickel Plating on Carbon Fiber with Palladium-Free Activation

2010 ◽  
Vol 148-149 ◽  
pp. 410-415
Author(s):  
Xiao Ping Luo ◽  
Ming Gang Zhang ◽  
Chun Xiang Lv
Keyword(s):  
Tensile Strength ◽  
Carbon Fiber ◽  
Fiber Surface ◽  
Electroless Nickel ◽  
Electroless Nickel Plating ◽  
Nickel Plating ◽  
Adhesive Properties ◽  
Nickel Deposition ◽  
X Ray ◽  
Electroless Ni

A new procedure of surface activation without using palladium salt is proposed for electroless nickel plating (Ni-P) on carbon fiber. The optimal formula and technical conditions for palladium-free activated electroless Ni-P were obtained by orthogonal experiments. The effects of nitric acid processing time on the quality of nickel coating was investigated .The effects of varying concentrations of Ni2 + on the rate of weight gain during the Ni2 + complex adsorption process were also analyzed and the kinetic equation of the process was established. The theoretical values calculated by the equation were proven to be consistent with the experimental verification. The material characteristics of the deposited layers were analyzed by scanning electron microscopy (SEM), energy-dispersive x-ray spectroscopy (EDX) and X-ray diffraction (XRD). The tensile strength of the carbon fibers was analyzed by the Weibull method, and this showed that when the thickness of the Ni-P coating reached 0.150μm, the tensile strength reached a maximum value. The experimental results showed that the nickel deposition on the carbon fiber surface obtained by this method, had the same uniformity, compactness and adhesive properties as the one by conventional electroless Ni-P.

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