scholarly journals An Integrated Imaging Study of the Pore Structure of the Cobourg Limestone—A Potential Nuclear Waste Host Rock in Canada

Minerals ◽  
2021 ◽  
Vol 11 (10) ◽  
pp. 1042
Author(s):  
Zhazha Hu ◽  
Shuangfang Lu ◽  
Jop Klaver ◽  
Jan Dewanckele ◽  
Alexandra Amann-Hildenbrand ◽  
...  
Keyword(s):  
Pore Structure ◽  
Imaging Study ◽  
Size Distributions ◽  
Micro Ct ◽  
Resolution Limit ◽  
Sem Images ◽  
Middle Ordovician ◽  
Pore Size Distributions ◽  
Structure Morphology ◽  
Capillary Bundle

With the development of imaging technology, tools to quantitatively describe pore structure, morphology, and connectivity have been widely applied on low permeable rocks; however, it is still questionable to what extent this information can be used to predict permeability. Applicability and comparability of different techniques are discussed here for the Middle Ordovician Cobourg limestone (Canada), a rock dominated by calcite grains of variable sizes (µm–cm) and heterogeneously distributed quartz, dolomite, pyrite, and meshy clay minerals. Absolute porosities determined by helium pycnometry (HP) in literature are approximately 1.6% (±0.9%), and gas permeabilities range from 10−20 to 10−19 m2. Porosities obtained from BIB-SEM are much smaller compared to those from HP (16–69% of HP). Pores found in clays are smaller, slit-shaped, and more densely spaced when compared to those in calcite minerals. Connectivity between pores could not be resolved with 3D micro-CT or FIB-SEM reconstructions, which have a resolution limit of 8 µm and 10 nm, respectively. However, assuming the pores to be connected, laboratory-derived permeability data could be fitted using a simple capillary bundle model, including information about the visible pore size distributions obtained from BIB-SEM images and a tortuosity range of 8 to 15.

Pore Structure of TiO2- Modified ZrO2 Particles Prepared by the Glycothermal Method

2020 ◽  
Vol 38 ◽  
pp. 17-22
Author(s):  
Fuya Sugiyama ◽  
Shunsuke Hayashi ◽  
Shinji Iwamoto
Keyword(s):  
Thermal Stability ◽  
Thermal Treatment ◽  
Pore Structure ◽  
High Performance ◽  
Spherical Particles ◽  
Size Distributions ◽  
Catalytic Materials ◽  
Surface Areas ◽  
Pore Size Distributions ◽  
Specific Surface Areas

Titania-modified zirconias with different Ti/Zr ratios were synthesized via thermal treatment of zirconium (IV) tetra-n-propoxide and titanium (IV) tetra-iso-propoxide in 1,4-butanediol at 300 °C. The obtained products were spherical particles composed of nanocrystals with the tetragonal ZrO2 structure. The products had large specific surface areas, large pore volumes, and relatively narrow pore size distributions in the mesopore region. After calcination at high temperatures, the obtained TiO2-modified ZrO2 samples preserved large surface areas and pore structure. Having these superior thermal stability and pore structure, the obtained TiO2-modified ZrO2 particles are expected to show high performance as catalytic materials.

scholarly journals Characterization of Shale Pore Structure by Multitechnique Combination and Multifractal Analysis and Its Significance

Geofluids ◽  
2020 ◽  
Vol 2020 ◽  
pp. 1-16
Author(s):  
Dengke Liu ◽  
Tao Tian ◽  
Ruixiang Liang ◽  
Fu Yang ◽  
Feng Ye
Keyword(s):  
Pore Structure ◽  
Pore Size ◽  
Multifractal Analysis ◽  
Ordos Basin ◽  
Pore Network ◽  
Size Distributions ◽  
Geochemical Parameters ◽  
Pore Size Distributions ◽  
Wide Range ◽  
Shale Reservoirs

Understanding pore structure would enable us to obtain a deeper insight into the fluid mechanism in porous media. In this research, multifractal analysis by various experiments is employed to analyze the pore structure and heterogeneity characterization in the source rock in Ordos Basin, China. For this purpose, imaging apparatus, intrusion tests, and nonintrusion methods have been used. The results show that the objective shale reservoir contains complex pore network, and minor pores dominant the pore system. Both intrusion and nonintrusion methods detected pore size distributions show multifractal nature, while the former one demonstrates more heterogeneous features. The pore size distributions acquired by low temperature adsorption and nuclear magnetic resonance have relatively good consistence, indicating that similar pore network detection method may share the same mechanism, and the full-ranged pore size distributions need to be acquired by multitechniques. Chlorite has an obvious impact on the heterogeneity of pore structure in narrow pore size range, while illite and I/S mixed layer influence that in wide range. Kerogen index is the fundamental indicators of geochemical parameters. With the decrease of averaged small and middle/large pore radius, the heterogeneity of pore structures increase in narrow and wide ranges, respectively. This work employed a comprehensive methodology based on multitechniques and helps to explore how pore networks affect reservoir quality in shale reservoirs.

scholarly journals Surfactant-Free Solvothermal Method for Synthesis of Mesoporous Nanocrystalline TiO2Microspheres with Tailored Pore Size

2013 ◽  
Vol 2013 ◽  
pp. 1-7 ◽  
Author(s):  
Yajing Zhang ◽  
Sujuan Zhang ◽  
Kangjun Wang ◽  
Fu Ding ◽  
Jing Wu
Keyword(s):  
Pore Size ◽  
Anatase Phase ◽  
Nitrogen Adsorption ◽  
Ethanol Solution ◽  
Tetrabutyl Titanate ◽  
Size Distributions ◽  
Pore Size Distributions ◽  
Structure Morphology ◽  
Mesoporous Microspheres ◽  
Adsorption Desorption

TiO2mesoporous microspheres self-assembled from nanoparticles were synthesized by a surfactant-free solvothermal route. The TiO2precursors were fabricated by tetrabutyl titanate, glacial acetic acid, and urea in the ethanol solution at 140°C for 20 h, and TiO2mesoporous microspheres were obtained by a postcalcination at temperatures of 450°C for promoting TiO2crystallization and the removal of residual organics. The phase structure, morphology, and pore nature were characterized by XRD, SEM, and nitrogen adsorption-desorption measurements. The as-prepared TiO2microspheres are in anatase phase, with 2-3 μm in diameter, and narrow pore distribution range is 3-4 nm. The adjustments of the synthetic parameters lead to the formation of the mesoporous TiO2microspheres with tuned pore size distributions and morphology.

scholarly journals Petrophysical Characterizations of Shale Gas Reservoirs of the Ranikot Formation in the Lower Indus Basin, Pakistan

2021 ◽  
Vol 3 (2) ◽  
pp. 103-107
Author(s):  
Kazunori Abe ◽  
Nouman Zobby ◽  
Hikari Fujii
Keyword(s):  
Pore Structure ◽  
Pore Size ◽  
Density Functional ◽  
Gas Flow ◽  
Slip Flow ◽  
Indus Basin ◽  
Size Distributions ◽  
Gas Reservoirs ◽  
Lower Indus Basin ◽  
Pore Size Distributions

The complex pore structure with nano-pores of shale gas reservoirs has an impact on the hydrocarbon storage and transport systems. We examined the pore structure of the shales of the Ranikot Formation in the Lower Indus Basin, Pakistan to investigate the full scaled pore size distributions by using a combination of techniques, mercury injection capillary pressure analysis and low pressure gas adsorption methods using N2 and CO2. Isotherm curves obtained N2 and CO2 adsorptions were interpreted using density functional theory analysis for describing the nano-scaled pore size distributions. The pore geometry of the shales was estimated to be slit-type from the isotherm hysteresis loop shape. The pore size distributions determined the density functional theory showed the dominant pore size of below around 10 nm. The Micro-scale effects such as slippage and adsorption/desorption also significantly influence the gas flow in nano-pore structure. The gas flow regimes in shales are classified into four types Darcy flow, slip flow, transition flow, Knudsen flow based on the value of the Knudsen number. Applying the specific reservoir conditions in Ranikot shale and pore size distribution to the Knudsen number, the gas flow regimes of the Ranikot shales were estimated mostly within the transition and slip flow.

Diffusion and Pore Structure in Portland Cement Pastes Blended with Low Calcium Fly Ash

1985 ◽  
Vol 65 ◽  
Author(s):  
Amitabha Kumar ◽  
Della M. Roy
Keyword(s):  
Fly Ash ◽  
Portland Cement ◽  
Pore Structure ◽  
Pore Size ◽  
Size Distributions ◽  
Cation Diffusion ◽  
Cement Pastes ◽  
Effective Coefficients ◽  
Pore Size Distributions ◽  
Diffusion Rates

ABSTRACTEffective coefficients for the diffusion of Cs+ and Cl− ions accross hardened plates of Portland cement and Portland cement-fly ash blend pastes were measured at 27°, 38° and 60° for samples cured up to 28 d. The porosity and pore size distributions of the same hardened plates were also determined. The fly ash blends show lower anion and cation diffusion rates at higher temperatures, although the porosity is not significantly different from the neat paste. The finer pore size is considered responsible for the slower diffusion in the blends. The electronegative nature of the pore surfaces also contributes to the slower cation diffusion.

Using X-Ray Micro-CT Imaging to Monitor Dissolution of Macroporous Bioactive Glass Scaffolds

2005 ◽  
Vol 284-286 ◽  
pp. 493-496 ◽  
Author(s):  
Julian R. Jones ◽  
Georgina E. Milroy ◽  
Ruth Cameron ◽  
William Bonfield ◽  
Larry L. Hench
Keyword(s):  
Bioactive Glass ◽  
Sol Gel ◽  
Size Distributions ◽  
Micro Ct ◽  
X Ray ◽  
Pore Size Distributions ◽  
Icp Analysis ◽  
Non Destructive ◽  
Interconnected Pore ◽  
Percentage Porosity

Bioactive glass scaffolds with interconnected macroporous networks have been developed by foaming sol-gel derived bioactive glass of the 70S30C (70 mol% SiO2, 30 mol% CaO) composition. The effect of sintering temperature on the dissolution of the scaffolds in simulated body fluid (SBF) was investigated in 3D using x-ray micro-computer tomography (micro CT) and inductive coupled plasma (ICP) analysis. Micro-CT is non-destructive and allows observation of specific parts of the scaffold at various stages of degradation. However, data analysis is complex at present. Percentage porosity data obtained by micro-CT was compared to physical data and pore size distributions obtained from mercury intrusion porosimetry were compared to the interconnected pore diameters observed from the micro CT images.

Study for Quantitative Analysis of Loess Microstructure Influence

2012 ◽  
Vol 594-597 ◽  
pp. 522-526
Author(s):  
Peng Ran Song ◽  
Chang Ming Wang
Keyword(s):  
Image Processing ◽  
Pore Size ◽  
Influence Factors ◽  
Fractal Dimensions ◽  
Engineering Properties ◽  
Size Distributions ◽  
Sem Images ◽  
Soil Microstructure ◽  
Computer Image Processing ◽  
Pore Size Distributions

Microstructure is a important index of soil physical, mechanical and engineering properties, SEM images and computer image processing technology make the soil microstructure research developing rapidly in recent years, but the researches on the influence factors and important degree are rare. Process the images form scanning electron microscopy test with the image processing toolbox of MATLAB. Fractal dimensions, porosities and pore size distributions are calculated in different analyzing windows, thresholds and magnifications. The results show that:1) As the results of the experiment influenced greatly by the smaller analyzing windows, in order to get the real calculation value, the medium section was processed; 2) Fractal dimension values are less influenced than porosities and pore size distributions by different thresholds; 3) Too big magnification can cause inaccurate fractal dimensions. Porosities and pore size distributions are inverse growing with increasing of magnification.

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