scholarly journals The influence of sample geometry on the permeability of a porous sandstone

2019 ◽  
Vol 8 (1) ◽  
pp. 55-61 ◽  
Author(s):  
Michael J. Heap
Keyword(s):  
Aspect Ratio ◽  
Gas Permeability ◽  
Physical And Mechanical Properties ◽  
Sample Length ◽  
Laboratory Measurements ◽  
Rock Samples ◽  
Porous Sandstone ◽  
Bulk Volume ◽  
Different Diameters ◽  
Cylindrical Samples

Abstract. Although detailed guidelines exist for measuring the physical and mechanical properties of laboratory rock samples, guidelines for laboratory measurements of permeability are sparse. Provided herein are gas permeability measurements of cylindrical samples of Darley Dale sandstone (with a connected porosity of 0.135 and a pore and grain size of 0.2–0.3 mm) with different diameters (10, 20, and 25 mm) and lengths (from 60 to 10 mm), corresponding to aspect (length ∕ diameter) ratios between 6.2 and 0.4. These data show that, despite the large range in sample length, aspect ratio, and bulk volume (from 29.7 to 1.9 cm3), the permeabilities of the Darley Dale sandstone samples are near identical (3–4×10-15 m2). The near-identical permeability of these samples is considered the consequence of the homogeneous porosity structure typical of porous sandstones and the small grain and pore size of Darley Dale sandstone with respect to the minimum tested diameter and length (both 10 mm). Laboratory permeability measurements on rock samples with inhomogeneous porosity structures or with larger grain and pore sizes may still provide erroneous values if their length, diameter, and/or aspect ratio is low. Permeability measurements on rocks with vastly different microstructural properties should now be conducted in a similar manner to help develop detailed guidelines for laboratory measurements of permeability.

scholarly journals The influence of sample geometry on the permeability of a porous sandstone

2018 ◽  
Author(s):  
Michael J. Heap
Keyword(s):  
Aspect Ratio ◽  
Gas Permeability ◽  
Physical And Mechanical Properties ◽  
Sample Length ◽  
Laboratory Measurements ◽  
Rock Samples ◽  
Porous Sandstone ◽  
Bulk Volume ◽  
Different Diameters ◽  
Cylindrical Samples

Abstract. Although detailed guidelines exist for measuring the physical and mechanical properties of laboratory rock samples, guidelines for laboratory measurements of permeability are sparse. Provided herein are gas permeability measurements of cylindrical samples of Darley Dale sandstone (with a connected porosity of 0.135 and a pore- and grain-size of 0.2–0.3 mm) with different diameters (10, 20, and 25 mm) and lengths (from 60 to 10 mm), corresponding to aspect (length/diameter) ratios between 6.2 and 0.4. These data show that, despite the large range in sample length, aspect ratio, and bulk volume (from 29.7 to 1.9 cm3), the permeabilities of the Darley Dale sandstone samples are near identical (3–4 × 10–15 m2). The near identical permeability of these samples is considered the consequence of the homogeneous porosity structure typical of porous sandstones, and the small grain- and pore-size of Darley Dale sandstone with respect to the minimum tested diameter and length (both 10 mm). Laboratory permeability measurements on rock samples with inhomogeneous porosity structures, or with larger grain- and pore-sizes, may still provide erroneous values if their length, diameter, and/or aspect ratio is low. Permeability measurements on rocks with vastly different microstructural properties should now be conducted in a similar manner to help develop detailed guidelines for laboratory measurements of permeability.

scholarly journals Kinetics of the Boride Layers Obtained on AISI 1018 Steel by Considering the Amount of Matter Involved

Coatings ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 259 ◽  
Author(s):  
Pablo A. Ruiz-Trabolsi ◽  
Julio Cesar Velázquez ◽  
Carlos Orozco-Álvarez ◽  
Rafael Carrera-Espinoza ◽  
Jorge A. Yescas-Hernández ◽  
...  
Keyword(s):  
Sample Size ◽  
Growth Kinetics ◽  
Duration Of Treatment ◽  
Solid Diffusion ◽  
Treatment Conditions ◽  
Wear And Corrosion ◽  
Different Diameters ◽  
Boriding Process ◽  
Kinetics Of ◽  
Cylindrical Samples

Boride layers are typically used to combat the wear and corrosion of metals. For this reason, to improve our knowledge of the boriding process, this research studied the effect of the size of the treated material on the kinetics of the growth of the boride layers obtained during a solid diffusion process. The purpose was to elucidate how the layers’ growth kinetics could be affected by the size of the samples since, as the amount of matter increases, the amount of energy necessary to make the process occur also increases. Furthermore, the level of activation energy seems to change as a function of the sample size, although it is considered an intrinsic parameter of each material. Six cylindrical samples with different diameters were exposed to the boriding process for three different exposure times (1.5, 3, and 5 h). The treatment temperatures used were 900, 950, and 1000 °C for each size and duration of treatment. The results show that the layer thickness increased not only as a function of the treatment conditions but also as a function of the sample diameter. The influence of the sample size on the growth kinetics of the boride layers is clear, because the growth rate increased even though the treatment conditions (time and temperature) remained constant.

Foam Flow in Different Pore Systems—Part 1: The Roles of Pore Attributes and Their Variation on Trapping and Apparent Viscosity of Foam

SPE Journal ◽  
2021 ◽  
pp. 1-18 ◽  
Author(s):  
Abdulrauf Rasheed Adebayo
Keyword(s):  
Porous Medium ◽  
Aspect Ratio ◽  
Pore Size ◽  
Coordination Number ◽  
Apparent Viscosity ◽  
Absolute Permeability ◽  
Surface Relaxation ◽  
Foam Flow ◽  
Rock Samples ◽  
Lower Permeability

Summary Lateral propagation of foam in heterogeneous reservoirs, where pore geometries vary laterally, depends on the roles of pore geometries on the foam properties. In this paper, the pore attributes of 12 different rock samples were characterized in terms of porosity, permeability, pore shape, pore size, throat size, aspect ratio, coordination number, and log mean of surface relaxation times (T2LM). These were measured from gas porosimeter and permeameter, X-ray microcomputed tomography (CT)-basedpore-network models, thin-section photomicrographs, and nuclear magnetic resonance (NMR) surface relaxometry. The samples have a wide range of porosity: 12 to 29%; permeability: 1 to 5,000 md; average pore size: 3.7 to 9 µm; average throat size: 2.4 to 8 µm; average aspect ratio: 1 to 1.7; average coordination number: 2.6 to 5.2; and T2LM: 9.4 to 740 ms. Nitrogen foam flow experiments (without oil) were then conducted on each rock sample using a specialized coreflood apparatus. A graphical analysis of the coreflood data was used to estimate the total saturation of trapped foam (10 to 66%), flowing foam (3 to 14%), and apparent viscosity of foam (3.2 to 73 cp). Trapped foam saturation and apparent viscosity values were then correlated with each of the measured pore attributes. The results revealed that all pore attributes, except aspect ratio, have positive correlations with foam trapping and apparent viscosity. The best correlation with trapped foam saturation was obtained when the most influential pore attributes (pore size, throat size, aspect ratio, and coordination number) were combined into a single mathematical function. Foam apparent viscosity also appears to be mostly influenced by trapped foam saturation, permeability, and coordination number of pore systems. Trapping is also likely enhanced by the presence of fenestral or channel pores. Furthermore, the shape and angularity of pores seem to facilitate snap-off and trapping of foam, because rock samples with angular pores trapped the highest foam saturation compared with other samples with rounded and subrounded pores. It was also shown that the correlation between trapped foam saturation (and foam apparent viscosity) and the absolute permeability of porous media may reverse at some high-permeability values (greater than several darcies), when one or both of the following conditions exist: (1) The aspect ratio of a lower-permeability porous medium is lower than that of a higher-permeability porous medium, and (2) the coordination number of a lower-permeability porous medium is higher than that of a higher-permeability porous medium. Finally, T2LM showed a good correlation with foam trapping, making NMR logging a prospective tool for pre-evaluating foam performance in targeted reservoir sections.

Gas permeability calculation of tight rocks based on laboratory measurements with non-ideal gas slippage and poroelastic effects considered

2018 ◽  
Vol 112 ◽  
pp. 16-24 ◽  
Author(s):  
Ziyan Wang ◽  
Reinhard Fink ◽  
Yue Wang ◽  
Alexandra Amann-Hildenbrand ◽  
Bernhard M. Krooss ◽  
...  
Keyword(s):  
Gas Permeability ◽  
Ideal Gas ◽  
Laboratory Measurements ◽  
Gas Slippage ◽  
Tight Rocks

scholarly journals The influence of physical and mechanical properties of additional materials on the recycled rubber structure during its disposal

2019 ◽  
Vol 116 ◽  
pp. 00002 ◽  
Author(s):  
Imad Rezakalla Antypas ◽  
Ghias Kharmanda ◽  
Alexey Dyachenko ◽  
Tatiana Savostina
Keyword(s):  
Mechanical Properties ◽  
Physical And Mechanical Properties ◽  
Stress Strain ◽  
Long Term Storage ◽  
Environmental Damages ◽  
Recycled Rubber ◽  
Different Diameters ◽  
Term Storage

During the rubber long-term storage in the open air and under the influence of certain temperatures, there is a real threat to the environment where environmental damages cannot be ignored. The objective of this paper is to study the mechanical properties of rubber during its processing by vulcanization after adding some materials to improve their properties. The used materials are: rubber from tires where the proportion of rubber varies from 70-78%, vulcanization granules of rubber, non-vulcanized natural NR rubber, and granulated sulphur. Curves of stress-strain of the recycled rubber are modelled at different diameters of the granules added to the materials for vulcanization removal. As result, the improvement of the mechanical properties are obtained by increasing the diameter of the granules but there a threshold which should not be exceeded.

Modeling squirt dispersion and attenuation in fluid-saturated rocks using pressure dependency of dry ultrasonic velocities

Geophysics ◽  
2012 ◽  
Vol 77 (3) ◽  
pp. WA157-WA168 ◽  
Author(s):  
Osni Bastos de Paula ◽  
Marina Pervukhina ◽  
Dina Makarynska ◽  
Boris Gurevich
Keyword(s):  
Aspect Ratio ◽  
Elastic Properties ◽  
Elastic Moduli ◽  
Pore Space ◽  
Geometrical Parameters ◽  
Laboratory Measurements ◽  
Significant Linear Trend ◽  
Aspect Ratios ◽  
Pressure Dependency ◽  
Dispersion And Attenuation

Modeling dispersion and attenuation of elastic waves in fluid-saturated rocks due to squirt flow requires the knowledge of a number of geometrical parameters of the pore space, in particular, the characteristic aspect ratio of the pores. These parameters are usually inferred by fitting measurements on saturated rocks to model predictions. To eliminate such fitting and thus make the model more predictive, we propose to recover the geometrical parameters of the pore space from the pressure dependency of elastic moduli on dry samples. Our analysis showed that the pressure dependency of elastic properties of rocks (and their deviation from Gassmann’s prediction) at ultrasonic frequencies is controlled by the squirt flow between equant, stiff, and so-called intermediate pores (with aspect ratios between [Formula: see text]). Such intermediate porosity is expected to close at confining pressures of between 200 and 2000 MPa, and thus cannot be directly obtained from ultrasonic experiments performed at pressures below 50 MPa. However, the presence of this intermediate porosity is inferred from the significant linear trend in the pressure dependency of elastic properties of the dry rock and the difference between the bulk modulus of the dry rock computed for spherical pores and the measured modulus at 50 MPa. Moreover, we can infer the magnitude of the intermediate porosity and its characteristic aspect ratio. Substituting these parameters into the squirt model, we have computed elastic moduli and velocities of the water-saturated rock and compared these predictions against laboratory measurements of these velocities. The agreement is good for a number of clean sandstones, but not unexpectedly worse for a broad range of shaley sandstones. Our predictions showed that dispersion and attenuation caused by the squirt flow between compliant and stiff pores may occur in the seismic frequency band. Confirmation of this prediction requires laboratory measurements of elastic properties at these frequencies.

Gas permeability and mechanical properties of PDMS mixed with PMPS nanofibers produced by electrospinning

2012 ◽  
Vol 1410 ◽  
Author(s):  
Atsushi Nakano ◽  
Norihisa Miki ◽  
Koichi Hishida ◽  
Atsushi Hotta
Keyword(s):  
Mechanical Properties ◽  
Fracture Strain ◽  
Gas Permeability ◽  
Phenyl Group ◽  
Pdms Membrane ◽  
Solubility Parameters ◽  
Permeability Test ◽  
Enhancement Mechanism ◽  
Siloxane Polymer ◽  
Different Diameters

ABSTRACTPolymethylphenylsilicone (PMPS), a siloxane polymer with a phenyl group, was first successfully electrospun to fabricate different diameters of silicone fibers ranging from 500 nm to 10 μm by considering solubility parameters of 12 different solvents. The resulting PMPS fibers were mixed with polydimethylsiloxane (PDMS) by retaining their original nanofiber structures to produce a polysiloxane-based nanofibrous composite. As for the mechanical properties, the PMPS/PDMS composite presented higher Young’s modulus and higher fracture strain than pure PDMS. The gas permeability test revealed that the PMPS/PDMS composite exhibited higher CO2 permeability than the pure PDMS membrane. Moreover, CO2 permeability gradually increased by raising the compounding ratio of PMPS-fibers in the PMPS/PDMS composite and by decreasing the diameter of PMPS-fibers. The enhancement mechanism observed in both mechanical properties and CO2 permeability was discussed from the viewpoint of the interface between PMPS and PDMS along with the nanofiber network structures.

scholarly journals The effect of saturation on the physical and mechanical behavior of some rock samples

2021 ◽  
Vol 2 (3) ◽  
pp. 23-31
Author(s):  
Mohammad Taghi Hamzaban
Keyword(s):  
Tensile Strength ◽  
Mechanical Behavior ◽  
Physical And Mechanical Properties ◽  
Intact Rock ◽  
P Wave ◽  
Mechanical Parameters ◽  
Brazilian Tensile Strength ◽  
Rock Samples ◽  
Rock Types ◽  
Major Factors

Different major factors control the strength of solid rocks. Moisture content is one of the most important factors, which can change the physical and mechanical behavior of intact rock as well as rock mass. Several early studies have shown that rock is weaker if tested wet rather than dry. In this paper, the density, P-wave velocity, uniaxial compressive strength, Brazilian tensile strength, and modulus of elasticity of seven different intact rock samples were measured under both dry and saturated conditions. The porosity of the samples was reported as well. Based on the obtained results, some correlations were proposed for estimating the saturated physical and mechanical properties from dry ones. The proposed correlations include different rock types and are more general than the previously reported ones. Comparing the obtained results showed that the mechanical and physical properties of weaker samples are more sensitive to the saturation process. Moreover, among the different mechanical parameters, Brazilian tensile strength exhibited more sensitivity to saturation. Comparing the results with the calculated porosities revealed that porosity is one of the key factors in the effect of saturation on physical and mechanical parameters. It seems that in the more porous rock samples, greater changes in the different measured parameters occur after saturation.

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