scholarly journals Examination of the fractal model for streaming potential coefficient in porous media

2019 ◽  
Vol 35 (1) ◽  
Author(s):  
Luong Duy Thanh
Keyword(s):  
Experimental Data ◽  
Porous Media ◽  
Zeta Potential ◽  
Streaming Potential ◽  
Fractal Model ◽  
Potential Coefficient ◽  
Proposed Model ◽  
Alternative Approach ◽  
High Fluid ◽  
Good Agreement

In this work, the fractal model for the streaming potential coefficient in porous media recently published has been examined by calculating the zeta potential from the measured streaming potential coefficient. Obtained values of the zeta potential are then compared with experimental data. Additionally, the variation of the streaming potential coefficient with fluid electrical conductivity is predicted from the model. The results show that the model predictions are in good agreement with the experimental data available in literature. The comparison between the proposed model and the Helmholtz-Smoluchowski (HS) equation is also carried out. It is seen that that the prediction from the proposed model is quite close to what is expected from the HS equation, in particularly at the high fluid conductivity or large grain diameters. Therefore, the model can be an alternative approach to obtain the zeta potential from the streaming potential measurements.

scholarly journals The temperature dependence of the zeta potential in porous media

2017 ◽  
Vol 33 (4) ◽  
Author(s):  
Luong Duy Thanh
Keyword(s):  
Experimental Data ◽  
Porous Media ◽  
Theoretical Model ◽  
Zeta Potential ◽  
Main Trend ◽  
Published Data ◽  
Average Increase ◽  
Different Temperatures ◽  
Increasing Temperature ◽  
Good Agreement

The measurements of the zeta potential of five consolidated samples including natural and artificial ceramic rocks saturated with 5.0×10-3 M NaCl electrolyte at different temperatures have been reported. The zeta potential obtained in this work is always negative and increases in magnitude with increasing temperature for all samples (an average increase of the zeta potential of 0.4 mV/ oC in magnitude). The experimental results are in good agreement with previously published data. The experimental data is then explained by a theoretical model. It is shown that the model is able to reproduce the main trend of the experimental data from our work and from published articles.

A fractal model for streaming potential coefficient in porous media

2017 ◽  
Vol 66 (4) ◽  
pp. 753-766 ◽  
Author(s):  
Luong Duy Thanh ◽  
Phan Van Do ◽  
Nguyen Van Nghia ◽  
Nguyen Xuan Ca
Keyword(s):  
Porous Media ◽  
Streaming Potential ◽  
Fractal Model ◽  
Potential Coefficient

scholarly journals Frequency-Dependent Streaming Potential of Porous Media—Part 2: Experimental Measurement of Unconsolidated Materials

2012 ◽  
Vol 2012 ◽  
pp. 1-17 ◽  
Author(s):  
P. W. J. Glover ◽  
E. Walker ◽  
J. Ruel ◽  
E. Tardif
Keyword(s):  
Porous Media ◽  
Steady State ◽  
Capillary Tube ◽  
Streaming Potential ◽  
Low Frequency ◽  
Theoretical Models ◽  
Potential Coefficient ◽  
Frequency Dependent ◽  
New Apparatus ◽  
Good Agreement

Frequency-dependent streaming potential coefficient measurements have been made upon Ottawa sand and glass bead packs using a new apparatus that is based on an electromagnetic drive. The apparatus operates in the range 1 Hz to 1 kHz with samples of 25.4 mm diameter up to 150 mm long. The results have been analysed using theoretical models that are either (i) based upon vibrational mechanics, (ii) treat the geological material as a bundle of capillary tubes, or (iii) treat the material as a porous medium. The best fit was provided by the Pride model and its simplification, which is satisfying as this model was conceived for porous media rather than capillary tube bundles. Values for the transition frequency were derived from each of the models for each sample and were found to be in good agreement with those expected from the independently measured effective pore radius of each material. The fit to the Pride model for all four samples was also found to be consistent with the independently measured steady-state permeability, while the value of the streaming potential coefficient in the low-frequency limit was found to be in good agreement with other steady-state streaming potential coefficient data.

scholarly journals A study on the variation of zeta potential with mineral composition of rocks and types of electrolyte

2018 ◽  
Vol 40 (2) ◽  
pp. 109-116
Author(s):  
Luong Duy Thanh ◽  
Rudolf Sprik
Keyword(s):  
Porous Media ◽  
Zeta Potential ◽  
Streaming Potential ◽  
Physical Review ◽  
Surface Site ◽  
Porous Rocks ◽  
Geophysical Research ◽  
Potential Coefficient ◽  
Electrokinetic Phenomena ◽  
Site Density

Streaming potential in rocks is the electrical potential developing when an ionic fluid flows through the pores of rocks. The zeta potential is a key parameter of streaming potential and it depends on many parameters such as the mineral composition of rocks, fluid properties, temperature etc. Therefore, the zeta potential is different for various rocks and liquids. In this work, streaming potential measurements are performed for five rock samples saturated with six different monovalent electrolytes. From streaming potential coefficients, the zeta potential is deduced. The experimental results are then explained by a theoretical model. From the model, the surface site density for different rocks and the binding constant for different cations are found and they are in good agreement with those reported in literature. The result also shows that (1) the surface site density of Bentheim sandstone mostly composed of silica is the largest of five rock samples; (2) the binding constant is almost the same for a given cation but it increases in the order KMe(Na+) < KMe(K+) < KMe(Cs+) for a given rock.References Corwin R. F., Hoovert D.B., 1979. The self-potential method in geothermal exploration. Geophysics 44, 226-245. Dove P.M., Rimstidt J.D., 1994. Silica-Water Interactions. Reviews in Mineralogy and Geochemistry 29, 259-308. Glover P.W.J., Walker E., Jackson M., 2012. Streaming-potential coefficient of reservoir rock: A theoretical model. Geophysics, 77, D17-D43. Ishido T. and Mizutani H., 1981. Experimental and theoretical basis of electrokinetic phenomena in rock-water systems and its applications to geophysics. Journal of Geophysical Research, 86, 1763-1775. Jackson M., Butler A., Vinogradov J., 2012. Measurements of spontaneous potential in chalk with application to aquifer characterization in the southern UK: Quarterly Journal of Engineering Geology & Hydrogeology, 45, 457-471. Jouniaux L. and T. Ishido, 2012. International Journal of Geophysics. Article ID 286107, 16p. Doi:10.1155/2012/286107. Kim S.S., Kim H.S., Kim S.G., Kim W.S., 2004. Effect of electrolyte additives on sol-precipitated nano silica particles. Ceramics International 30, 171-175. Kirby B.J. and Hasselbrink E.F., 2004. Zeta potential of microfluidic substrates: 1. Theory, experimental techniques, and effects on separations. Electrophoresis, 25, 187-202. Kosmulski M., and Dahlsten D., 2006. High ionic strength electrokinetics of clay minerals. Colloids and Surfaces, A: Physicocemical and Engineering Aspects, 291, 212-218. Lide D.R., 2009, Handbook of chemistry and physics, 90th edition: CRC Press. Luong Duy Thanh, 2014. Electrokinetics in porous media, Ph.D. Thesis, University of Amsterdam, the Netherlands. Luong Duy Thanh and Sprik R., 2016a. Zeta potential in porous rocks in contact with monovalent and divalent electrolyte aqueous solutions, Geophysics, 81, D303-D314. Luong Duy Thanh and Sprik R., 2016b. Permeability dependence of streaming potential coefficient in porous media. Geophysical Prospecting, 64, 714-725. Luong Duy Thanh and Sprik R., 2016c. Laboratory Measurement of Microstructure Parameters of Porous Rocks. VNU Journal of Science: Mathematics-Physics 32, 22-33. Mizutani H., Ishido T., Yokokura T., Ohnishi S., 1976. Electrokinetic phenomena associated with earthquakes. Geophysical Research Letters, 3, 365-368. Ogilvy A.A., Ayed M.A., Bogoslovsky V.A., 1969. Geophysical studies of water leakage from reservoirs. Geophysical Prospecting, 17, 36-62. Onsager L., 1931. Reciprocal relations in irreversible processes. I. Physical Review, 37, 405-426. Revil A. and Glover P.W.J., 1997. Theory of ionic-surface electrical conduction in porous media. Physical Review B, 55, 1757-1773. Scales P.J., 1990. Electrokinetics of the muscovite mica-aqueous solution interface. Langmuir, 6, 582-589. Behrens S.H. and Grier D.G., 2001. The charge of glass and silica surfaces. The Journal of Chemical Physics, 115, 6716-6721. Stern O., 1924. Zurtheorieder electrolytischendoppelschist. Z. Elektrochem, 30, 508-516. Tchistiakov A.A., 2000. Physico-chemical aspects of clay migration and injectivity decrease of geothermal clastic reservoirs: Proceedings World Geothermal Congress, 3087-3095. Wurmstich B., Morgan F.D., 1994. Modeling of streaming potential responses caused by oil well pumping. Geophysics, 59, 46-56. 

scholarly journals Modelling the Characteristics of Ring-Shaped Magnetoelastic Force Sensor in Mohri’s Configuration

Sensors ◽  
2020 ◽  
Vol 20 (1) ◽  
pp. 266 ◽  
Author(s):  
Anna Ostaszewska-Liżewska ◽  
Roman Szewczyk ◽  
Peter Raback ◽  
Mika Malinen
Keyword(s):  
Experimental Data ◽  
High Sensitivity ◽  
Force Sensor ◽  
Inhomogeneous Distribution ◽  
The Finite Element Method ◽  
The Core ◽  
Magnetoelastic Effect ◽  
Proposed Model ◽  
Distribution Of Stresses ◽  
Good Agreement

Magnetoelastic force sensors exhibit high sensitivity and robustness. One commonly used configuration of force sensor with a ring-shaped core was presented by Mohri at al. In this configuration force is applied in the direction of a diameter of the core. However, due to inhomogeneous distribution of stresses, model of such sensor has not been presented yet. This paper is filling the gap presenting a new method of modelling the magnetoelastic effect, which is especially suitable for the finite element method. The presented implementation of proposed model is in good agreement with experimental data and creates new possibilities of modelling other devices utilizing magnetoelastic effect.

Analysis and Validation of Cutting Forces Prediction Models in Micromachining

2006 ◽  
Vol 526 ◽  
pp. 13-18 ◽  
Author(s):  
H. Perez ◽  
Antonio Vizan Idoipe ◽  
J. Perez ◽  
J. Labarga
Keyword(s):  
Experimental Data ◽  
Cutting Force ◽  
Cutting Forces ◽  
Prediction Models ◽  
Precision Machining ◽  
New Model ◽  
Proposed Model ◽  
On Line ◽  
Machine Control ◽  
Good Agreement

Many investigations have been developed related to precision machining with features in the millimetre scale. In this paper different cutting force models for micromilling are analyzed and compared. A new model based on specific cutting force that also considers run-out errors has been developed. The estimated cutting forces obtained with this model had good agreement with the experimental data. Also, the proposed model allows to be implemented within the machine control for the on-line optimization of the micromilling process.

A NEW RELATIVE PERMEABILITY MODEL OF UNSATURATED POROUS MEDIA BASED ON FRACTAL THEORY

Fractals ◽  
2020 ◽  
Vol 28 (01) ◽  
pp. 2050002
Author(s):  
KE CHEN ◽  
HE CHEN ◽  
PENG XU
Keyword(s):  
Experimental Data ◽  
Porous Media ◽  
Fractal Dimension ◽  
Multiphase Flow ◽  
Relative Permeability ◽  
Volume Fraction ◽  
Fractal Model ◽  
Accurate Estimation ◽  
Unsaturated Porous Media ◽  
Flow Through

The multiphase flow through unsaturated porous media and accurate estimation of relative permeability are significant for oil and gas reservoir, grounder water resource and chemical engineering, etc. A new fractal model is developed for the multiphase flow through unsaturated porous media, where multiscale pore structure is characterized by fractal scaling law and the trapped water in the pores is taken into account. And the analytical expression for relative permeability is derived accordingly. The relationships between the relative permeability and capillary head as well as saturation are determined. The proposed model is validated by comparison with 14 sets of experimental data, which indicates that the fractal model agrees well with experimental data. It has been found that the proposed fractal model shows evident advantages compared with BC-B model and VG-M model, especially for the porous media with fine content and texture. Further calculations show that water permeability decreases as the fractal dimension increases under fixed saturation because the cumulative volume fraction of small pores increases with the increment of the fractal dimension. The present fractal model for the relative permeability may be helpful to understand the multiphase flow through unsaturated porous media.

Seismo-electric Conversion in Sandstones and Shales using 2 Different Experimental Approaches, Modelling and Theory

2020 ◽  
Author(s):  
Paul Glover ◽  
Rong Peng ◽  
Piroska Lorinczi ◽  
Bangrang Di
Keyword(s):  
Zeta Potential ◽  
Numerical Modelling ◽  
Clay Minerals ◽  
Shale Gas ◽  
Streaming Potential ◽  
Oil Reservoirs ◽  
Low Permeability ◽  
Experimental Measurements ◽  
Frequency Range ◽  
Potential Coefficient

&lt;p&gt;The development of seismo-electric (SE) exploration techniques relies significantly upon being able to understand and quantify the strength of frequency-dependent SE conversion. However, there have been very few SE measurements or modelling carried out. In this paper we present two experimental methods for making such measurements, and examine how the strength of SE conversion depends on frequency, porosity, permeability, and why it is unusual in shales. The first is based on an electromagnetic shaker and can be used in the 1 Hz to 2 kHz frequency range. The second is a piezo-electric water-bath apparatus which can be used in the 1kHz to 500 kHz frequency range.&lt;/p&gt;&lt;p&gt;The first apparatus has been tested on samples of Berea sandstone. Both the in-phase and in-quadrature components of the streaming potential coefficient have been measured with an uncertainty of better than &amp;#177;4%. The experimental measurements show the critical frequency at which the quadrature component is maximal, and the frequency of this component is shown to agree very well with both permeability and grain size. The experimental measurements have been modelled using several different methods.&lt;/p&gt;&lt;p&gt;The second apparatus was used to measure SE coupling as a function of porosity and permeability, interpreting the results using a micro-capillary model and current theory. We found a general agreement between the theoretical curves and the test data, indicating that SE conversion is enhanced by increases in porosity over a range of different frequencies. However, SE conversion has a complex relationship with rock permeability, which changes with frequency, and which is more sensitive to changes in the petrophysical properties of low-permeability samples. This observation suggests that seismic conversion may have advantages in characterizing low permeability reservoirs such as tight gas and tight oil reservoirs as well as shale gas reservoirs.&lt;/p&gt;&lt;p&gt;We have also carried out SE measurements on Sichuan Basin shales (permeability 1.47 &amp;#8211; 107 nD), together with some comparative measurements on sandstones (0.2 &amp;#8211; 60 mD). Experimental results show that SE conversion in shales is comparable to that exhibited by sandstones, and is approximately independent of frequency in the seismic frequency range (&lt;1 kHz). Anisotropy which arises from bedding in the shales results in anisotropy in the streaming potential coefficient. Numerical modelling has been used to examine the effects of varying zeta potential, porosity, tortuosity, dimensionless number and permeability. It was found that SE conversion is highly sensitive to changes in porosity, tortuosity and zeta potential in shales. Numerical modelling suggests that the cause of the SE conversion in shales is enhanced zeta potentials caused by clay minerals, which are highly frequency dependent. This is supported by a comparison of our experimental data with numerical modelling as a function of clay mineral composition from XRD measurements. Consequently, the sensitivity of SE coupling to the clay minerals suggests that SE exploration may have potential for the characterization of clay minerals in shale gas and shale oil reservoirs.&lt;/p&gt;

Novel Model for the Optical Function: Application to Hexagonal Gan

2001 ◽  
Vol 677 ◽  
Author(s):  
Y. Chan ◽  
Aleksandra B. Djurišić ◽  
E. Herbert Li
Keyword(s):  
Experimental Data ◽  
Closed Form ◽  
Dielectric Function ◽  
Absorption Edge ◽  
Low Energy ◽  
Optical Function ◽  
Complex Dielectric Function ◽  
Proposed Model ◽  
Novel Model ◽  
Good Agreement

ABSTRACTIn this work we propose an analytical expression for the complex dielectric function that includes both discrete and continuum exciton effects. The model is based on the work of Elliott and the proposed model has been applied to modeling the experimental data for the hexagonal GaN. We have obtained good agreement with the experimental data. The model assumes Lorentzian broadening in order to obtain dielectric function equations in analytically closed form. We show that Lorentzian broadened dielectric function decays more slowly than the experimental data for hexagonal GaN at the low energy side. This indicates that the broadening of the absorption edge in GaN is not purely Lorentzian. The agreement with the experimental data can be improved using adjustable broadening modification.

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