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Our recent work on deep tight gas reservoirs containing red and white sandstones (Potter et al., 2009) has shown that the presence of small amounts of hematite in reservoir samples has a dramatic effect on permeability. Such concl...
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Our recent work on deep tight gas reservoirs containing red and white sandstones (Potter et al., 2009) has shown that the presence of small amounts of hematite in reservoir samples has a dramatic effect on permeability. Such conclusions were made using laboratory based low and high field magnetic susceptibility measurements on reservoir rock samples and by comparing these measurements with the permeability data. These rapid, non-destructive magnetic measurements have previously been applied in clastic reservoir samples (Potter, 2005, 2007; Ivakhnenko, 2006; Ivakhnenko and Potter, 2006, 2008; Potter and Ivakhnenko 2007, 2008) and carbonate reservoir samples (AlGhamdi, 2006; Potter et al 2008). However, such laboratory based analyses are not representative of the downhole in-situ conditions, especially in deep gas reservoirs where temperature can reach quite high values. Typical tight gas reservoir depths can reach to about 4000m (Abu-Shanab et al 2005) and 6000m (Jianming et al 2008) and the equivalent temperatures would measure 131 ℃ and 192 ℃ respectively (Mayer-Gurr, 1976).This paper investigates the in-situ magnetic properties of permeability controlling reservoir minerals (hematite and illite in this case) via laboratory experiments to model downhole conditions. We perform magnetic hysteresis measurements at various temperatures in order to 1) quantify mineralogy and 2) to show changes in the magnetic behaviour of these minerals at in-situ downhole conditions. From these measurements, we are able to show whether the mineralogy and/or domain state of these permeability controlling minerals is likely to change with temperature in the deep gas reservoirs. This can have a major impact on permeability.We also show some results from another red and white tight gas reservoir where there is a strong correlation between core permeability and magnetic susceptibility data. In this particular reservoir, the presence of siderite in the white sections of the core greatly improves permeability. Once again for this reservoir, the permeability is low in red sections of the core due to the presence of hematite.
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Current measuring is the core precondition for relay protection, energy metering and Rogowski coil is one of the most favorable transformers. In this paper, the effects of geometrical parameters of Rogowski coil on its performance...
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Current measuring is the core precondition for relay protection, energy metering and Rogowski coil is one of the most favorable transformers. In this paper, the effects of geometrical parameters of Rogowski coil on its performance are calculated and compared to provide a general overview of geometrical selection. The expressions of mutual inductance of rectangular, circular and oval winding coil are derived and calculated, and the reliabilities of each shape of the coil are compared by the simulation. The results show that in condition of equal section area, the mutual inductance of rectangular, circular and oval winding coil are in descending sequences and the relative error of oval winding coil is the smallest, which is helpful for obtaining accurate current values. The research provides important guidance for the rapid and reasonable geometrical selection of Rogowski coil in engineering applications.
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摘要 :
Current measuring is the core precondition for relay protection, energy metering and Rogowski coil is one of the most favorable transformers. In this paper, the effects of geometrical parameters of Rogowski coil on its performance...
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Current measuring is the core precondition for relay protection, energy metering and Rogowski coil is one of the most favorable transformers. In this paper, the effects of geometrical parameters of Rogowski coil on its performance are calculated and compared to provide a general overview of geometrical selection. The expressions of mutual inductance of rectangular, circular and oval winding coil are derived and calculated, and the reliabilities of each shape of the coil are compared by the simulation. The results show that in condition of equal section area, the mutual inductance of rectangular, circular and oval winding coil are in descending sequences and the relative error of oval winding coil is the smallest, which is helpful for obtaining accurate current values. The research provides important guidance for the rapid and reasonable geometrical selection of Rogowski coil in engineering applications.
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The complex permeability and composite materials are made form Ni_(0,36)Zn_(0,64) Fe_2O_4 ferrite material and the basic frequency characteristics and material properties will be presented in this article. The frequency range was ...
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The complex permeability and composite materials are made form Ni_(0,36)Zn_(0,64) Fe_2O_4 ferrite material and the basic frequency characteristics and material properties will be presented in this article. The frequency range was measured up to 1 GHz. We found the possibilities how to predict behaviour of these composites up that frequency. It was realized basically on complex permeability and mathematical model of these ferrite materials.
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Through press mercury test,scanning electron microcopy observation and hydraulic servo controller test,the porosity and permeable characteristics of low permeable rock were analyzed,the result indicates that the initial and the ma...
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Through press mercury test,scanning electron microcopy observation and hydraulic servo controller test,the porosity and permeable characteristics of low permeable rock were analyzed,the result indicates that the initial and the maximum permeability of the rocks of most layers in the area is all low,which belong to low permeable aquifer. The conclusion is identical to the site pump test results.
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摘要 :
Through press mercury test,scanning electron microcopy observation and hydraulic servo controller test,the porosity and permeable characteristics of low permeable rock were analyzed,the result indicates that the initial and the ma...
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Through press mercury test,scanning electron microcopy observation and hydraulic servo controller test,the porosity and permeable characteristics of low permeable rock were analyzed,the result indicates that the initial and the maximum permeability of the rocks of most layers in the area is all low,which belong to low permeable aquifer. The conclusion is identical to the site pump test results.
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The interaction between a tubular beam of charged particles and a dispersive medium of cylindrical configuration has been investigated. This medium may have negative permittivity and negative permeability simultaneously over a cer...
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The interaction between a tubular beam of charged particles and a dispersive medium of cylindrical configuration has been investigated. This medium may have negative permittivity and negative permeability simultaneously over a certain frequency range. The dispersion equation for the eigenmodes spectra of a medium and the coupled modes spectra of the system have been derived and numerically analyzed. It has been found that the absolute beam instability of bulk-surface waves occurs because of peculiarities of the eigenmodes spectra of a left-handed metamaterial. The resonant frequency behavior of the permeability causes the emergence of the sections of dispersion curves with anomalous dispersion. The obtained results allow us to propose the left-handed metamaterial as the delaying medium in oscillators of electromagnetic radiation without a need to provide an additional feedback in the system.
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摘要 :
The interaction between a tubular beam of charged particles and a dispersive medium of cylindrical configuration has been investigated. This medium may have negative permittivity and negative permeability simultaneously over a cer...
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The interaction between a tubular beam of charged particles and a dispersive medium of cylindrical configuration has been investigated. This medium may have negative permittivity and negative permeability simultaneously over a certain frequency range. The dispersion equation for the eigenmodes spectra of a medium and the coupled modes spectra of the system have been derived and numerically analyzed. It has been found that the absolute beam instability of bulk-surface waves occurs because of peculiarities of the eigenmodes spectra of a left-handed metamaterial. The resonant frequency behavior of the permeability causes the emergence of the sections of dispersion curves with anomalous dispersion. The obtained results allow us to propose the left-handed metamaterial as the delaying medium in oscillators of electromagnetic radiation without a need to provide an additional feedback in the system.
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Generally, a suitable polymer for using as pH indicator packaging should exhibit high porosity to provide a maximum gas permeability which lead to an accurate detection. Ethylene vinyl acetate (EVA) is normally used as such applic...
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Generally, a suitable polymer for using as pH indicator packaging should exhibit high porosity to provide a maximum gas permeability which lead to an accurate detection. Ethylene vinyl acetate (EVA) is normally used as such application. However, the gas permeability of EVA was fairly low as 1685.0940 cc/(m~2-day) which not good enough for used as pH indicator packaging application is. To increase a permeability of gas, high porous diatom incorporating with biopolymer was mixed into EVA polymer via internal mixer. It was found that the gas permeability of EVA filled porous diatom/biopolymer was increased up to 4204.2225 cc/(m~2-day). This property is one of the crucial properties for further design for pH indicator packaging in NHAM product.
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This paper reviews technical development of the emerging ASCE standard for permeable interlocking concrete pavement or PICP. The draft standard notes key design elements which include high strength, impermeable concrete units for ...
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This paper reviews technical development of the emerging ASCE standard for permeable interlocking concrete pavement or PICP. The draft standard notes key design elements which include high strength, impermeable concrete units for a pavement surface that meet ASTM or CSA standards. When installed, the joints between units are filled with permeable aggregate. The units are placed over an open-graded aggregate bedding course which rests on an open-graded aggregate base and subbase for water storage andstructural support. While common to all permeable pavements, the document provides a design flow chart for structural and hydrologic design and outlines three commonly used infiltration approaches determined by site and subgrade conditions, as well as designs for sloped subgrades. The draft standard addresses structural design for supporting traffic by modifying conventional flexible pavement design methodology from the American Association of State Highway and Transportation Officials and incorporatesthe effects of subgrade saturation researched by the University of California Davis. The draft resolves a key design consideration common to all three permeable pavements; the dichotomy between not compacting the soil subgrade for infiltration and compacting for enhanced structural support especially in saturated conditions. Besides guide construction specifications, construction and maintenance guidelines are provided via checklists. A key tool for assessing surface infiltration and subsequent vacuum cleaning is adoption of an ASTM surface infiltration test for PICP.
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