The Experts below are selected from a list of 303 Experts worldwide ranked by ideXlab platform
André Revil - One of the best experts on this subject based on the ideXlab platform.
-
Streaming Potential Coupling Coefficient and Transport Properties of Unsaturated Carbonate Rocks
Vadose Zone Journal, 2018Co-Authors: Aurélien Cherubini, Adrian Cerepi, Bruno Garcia, André RevilAbstract:We measured the Streaming Potential coupling coefficient of natural saturated and unsaturated carbonate rocks. Saturation was achieved with NaCl brines with salinities ranging from 2 ´ 10−3 to 2.0 mol L−1. The magnitude of the coupling coefficient increased with decreasing salinity, similarly to the trend observed for sandstones. The permeability had a low impact on the values of the Streaming Potential coupling coefficient at high and low salinity. The zeta Potential was calculated at full saturation using a modified version of the Helmholtz–Smoluchowski equation that accounts for surface electrical conductivity. Under atmospheric conditions, the magnitude of the zeta Potential decreased with the increase in salinity. We also explored the relationships between the Streaming Potential coupling coefficient and water saturation in three partially saturated limestones using a steady-state flow experiment. We found good agreement between the van Genuchten approach and experimental data, and fitted both the relative permeability and capillary pressure curves with the same value of the van Genuchten exponent mv. We validated the predictive water relative permeability model described by Revil in water-wet rocks when the second fluid phase is non-polar.
-
Streaming Potential coupling coefficient in unsaturated carbonate rocks
Geophysical Journal International, 2017Co-Authors: Adrian Cerepi, Aurélien Cherubini, Bruno Garcia, Hervé Deschamps, André RevilAbstract:The seismoelectric and self-Potential methods are showing promises to characterize both the vadose zone of the Earth, hydrocarbon reservoirs and CO2 sequestration. That said, the dependence of a key parameter, the Streaming coupling coefficient, with the saturation remains highly debated. We explore here the relationship between the Streaming Potential coupling coefficient, the electrical resistivity, the capillary pressure curves and the permeability in two saturated and partially saturated carbonate rocks characterized by distinct textures. We investigate a limestone from the Paris basin (the Brauvilliers limestone) and a dolostone from the Aquitain basin (sample labeled LS2), both in France. The two core samples are characterized in terms of their porosity and intrinsic formation factor. A new core flooding system is used to measure simultaneously and, for the first time, both the relative permeability, the resistivity index and the Streaming Potential coupling coefficient in steady-state two-phase flow conditions as a function of the saturation with CO2 or N2. The results are compared with a recently developed theoretical model, which can accommodate either the Brooks and Corey model or the van Genuchten model for the capillary pressure curves. This model is predicting a set of relationships between the Streaming Potential coupling coefficient, the relative permeability and the second Archie's exponent. We found a good agreement between the model based on the van Genuchten approach and experimental data, but still we could not fit all the curves with the same value of the pore size index λ or van Genuchten exponent mv especially for the relative permeability.
-
Streaming Potential in porous media 2 theory and application to geothermal systems
Journal of Geophysical Research, 1999Co-Authors: André Revil, H Schwaeger, Lawrence M Cathles, P D ManhardtAbstract:Self-Potential electric and magnetic anomalies are increasingly being observed associated with hydrothermal fields, volcanic activity, and subsurface water flow. Until now a formal theoretical basis for predicting Streaming Potential of porous materials has not been available. We develop here a model giving both the macroscopic constitutive equations and the material properties entering these equations. The material properties, like the Streaming Potential coupling coefficient, depend on pore fluid salinity, temperature, water and gas saturations, mean grain diameter, and porosity. Some aspects of the model are directly tested with success against laboratory data. The Streaming Potential increases with temperature, grain size, and gas saturation, and decreases with salinity. At the scale of geological structures the model provides an explanation for the presence of kilometer-scale dipolar self-Potential anomalies in geothermal systems and volcanoes. Positive self-Potential anomalies are associated with fluid discharge areas, whereas negative self-Potential anomalies are associated with fluid recharge areas. Self-Potential anomaly maps determined at the surface of active hydrothermal fields appear to be a powerful way of mapping the fluid recharge and discharge areas. In the case of free convection the vorticities of the convection pattern generate a magnetic field. The greater these vorticities, the greater the associated magnetic field. It follows that hydrothermal systems act as natural geobatteries because of the flow of pore fluids in the subsurface of these systems.
Dennis C Prieve - One of the best experts on this subject based on the ideXlab platform.
-
Streaming Potential near a rotating porous disk.
Langmuir : the ACS journal of surfaces and colloids, 2014Co-Authors: Dennis C Prieve, Paul J SidesAbstract:Theory and experimental results for the Streaming Potential measured in the vicinity of a rotating porous disk-shaped sample are described. Rotation of the sample on its axis draws liquid into its face and casts it from the periphery. Advection within the sample engenders Streaming current and Streaming Potential that are proportional to the zeta Potential and the disk's major dimensions. When Darcy's law applies, the Streaming Potential is proportional to the square of the rotation at low rate but becomes invariant with rotation at high rate. The Streaming Potential is invariant with the sample's permeability at low rate and is proportional to the inverse square of the permeability at high rate. These predictions were tested by determining the zeta Potential and permeability of the loop side of Velcro, a sample otherwise difficult to characterize; reasonable values of -56 mV for zeta and 8.7 × 10(-9) m(2) for the permeability were obtained. This approach offers the ability to determine both the zeta Potential and the permeability of materials having open structures. Compressing them into a porous plug is unnecessary. As part of the development of the theory, a convenient formula for a flow-weighted volume-averaged space-charge density of the porous medium, -εζ/k, was obtained, where ε is the permittivity, ζ is the zeta Potential, and k is the Darcy permeability. The formula is correct when Smoluchowski's equation and Darcy's law are both valid.
-
Calculation of the Streaming Potential near a rotating disk.
Langmuir : the ACS journal of surfaces and colloids, 2006Co-Authors: Paul J Sides, John Newman, James D Hoggard, Dennis C PrieveAbstract:A corrected theory of the Streaming Potential in the vicinity of a disk-shaped sample rotating in an electrolytic solution is presented. When Streaming-Potential measurements on a variety of materials were reduced to a zeta Potential according to a prior theory, the results exceeded expected values by a factor of approximately 2, even though other aspects of the same experiments seemed to confirm the theory. Investigation of the source of the discrepancy revealed a flaw in the prior theory. The crucial understanding is that the surface current produced by the rotation of the disk emerges from the diffuse layer and enters the bulk solution at the periphery of the disk. The new treatment accounts entirely for the discrepancy between literature data and results based on the prior theory.
-
calculation of the Streaming Potential near a rotating disk
Langmuir, 2006Co-Authors: Paul J Sides, John Newman, James D Hoggard, Dennis C PrieveAbstract:A corrected theory of the Streaming Potential in the vicinity of a disk-shaped sample rotating in an electrolytic solution is presented. When Streaming-Potential measurements on a variety of materi...
-
Electrohydrodynamics of thin double layers: a model for the Streaming Potential profile
Journal of Colloid and Interface Science, 1992Co-Authors: Stacy G. Bike, Dennis C PrieveAbstract:Abstract The motion of an electrolyte solution past a charged surface gives rise to convection of the ions within the double layer surrounding the surface. To conserve charge a Streaming Potential arises, generating an electrokinetic force on the surface. We have previously calculated this force in the lubrication limit for two bodies bearing thin, equilibrium double layers and moving slowly relative to each other; for this case, the Streaming Potential satisfies an equation analogous to Reynolds equation for the pressure. In this paper, we relax the lubrication approximation and address the electrohydrodynamics of thin double layers with regard to the Streaming Potential profile. Outside the double layer, the Streaming Potential satisfies Laplace's equation. We have developed a boundary condition for the Streaming Potential from the requirement of charge conservation at the outer edge of the double layer despite nonuniform convection inside the double layer. In particular, at the outer edge of the double layer the normal derivative of the Streaming Potential is directly proportional to the normal derivative of pressure profile generated by motion. We illustrate the solution of Laplace's equation using this boundary condition by calculating the dipole moment generated by a charged sphere sedimenting in an unbounded electrolyte solution (the Dorn effect) and the electrokinetic lift force on a charged sphere translating parallel to a distant wall.
Zbigniew Adamczyk - One of the best experts on this subject based on the ideXlab platform.
-
fibrinogen adsorption on mica studied by afm and in situ Streaming Potential measurements
Langmuir, 2011Co-Authors: Monika Wasilewska, Zbigniew AdamczykAbstract:Adsorption of fibrinogen from aqueous solutions on mica was studied using AFM and in situ Streaming Potential measurements. In the first stage, bulk physicochemical properties of fibrinogen and the mica substrate were characterized for various ionic strength and pH. The zeta Potential and number of uncompensated (electrokinetic) charges on the protein surfaces were determined from microelectrophoretic measurements. Analogously, using Streaming Potential measurements, the electrokinetic charge density of mica was determined for pH range 3−10 and the NaCl background electrolyte concentration of 10−3 and 10−2 M. Next, the kinetics of fibrinogen adsorption at pH 3.5 and 7.4 in the diffusion cell was studied using a direct AFM determination of the number of molecules per unit area of the mica substrate. Then, Streaming Potential measurements were performed to determine the apparent zeta Potential of fibrinogen-covered mica for different pH and ionic strength in terms of its surface concentration. A quantitativ...
-
Streaming current and Streaming Potential for particle covered surfaces virial expansion and simulations
Journal of Chemical Physics, 2009Co-Authors: Krzysztof Sadlej, Eligiusz Wajnryb, Jerzy Blawzdziewicz, Maria L Ekieljezewska, Zbigniew AdamczykAbstract:Streaming Potential changes induced by deposition of particles at solid/liquid interfaces are considered theoretically. The solution is obtained in terms of a virial expansion of the Streaming Potential up to the third order of the surface coverage of particles, assumed to be distributed according to the hard sphere equilibrium distribution function. Theoretical methods, including the idea of cluster expansion, are adopted from statistical physics. In the cluster expansion, two-body and three-body hydrodynamic interactions are evaluated with a high precision using the multipole method. The multipole expansion algorithm is also used to perform numerical simulations of the Streaming Potential, valid for the entire surface coverage range met in practice. Results of our calculations are in good agreement with the experimental data for spherical latex particles adsorbed on a mica surface.
-
characterization of polyelectrolyte multilayers by the Streaming Potential method
Langmuir, 2004Co-Authors: Zbigniew Adamczyk, Maria Zembala, Piotr Warszynski, Barbara JachimskaAbstract:Polyelectrolyte multilayer adsorption on mica was studied by the Streaming Potential method in the parallel-plate channel setup. The technique was calibrated by performing model measurements of Streaming Potential by using monodisperse latex particles. Two types of polyelectrolytes were used in our studies: poly(allylamine) hydrochloride (PAH), of a cationic type, and poly(sodium 4-styrenesulfonate) (PSS) of an anionic type, both having molecular weight of 70,000. The bulk characteristics of polymers were determined by measuring the specific density, diffusion coefficient for various ionic strengths, and zeta Potential. These measurements as well as molecular dynamic simulations of chain shape and configurations suggested that the molecules assume an extended, wormlike shape in the bulk. Accordingly, the diffusion coefficient was interpreted in terms of a simple hydrodynamic model pertinent to flexible rods. These data allowed a proper interpretation of polyelectrolyte multilayer adsorption from NaCl solutions of various concentrations or from 10(-3) M Tris buffer. After completing a bilayer, periodic variations in the apparent zeta Potential between positive and negative values were observed for multilayers terminated by PAH and PSS, respectively. These limiting zeta Potential values correlated quite well with the zeta Potential of the polymers in the bulk. The stability of polyelectrolyte films against prolonged washing (reaching 26 h) also was determined using the Streaming Potential method. It was demonstrated that the PSS layer was considerably more resistant to washing, compared to the PAH layer. It was concluded that the experimental data were consistent with the model postulating particle-like adsorption of polyelectrolytes with little chain interpenetration. It also was concluded that due to high sensitivity, the electrokinetic method applied can be effectively used for quantitative studies of polyelectrolyte adsorption, desorption, and reconformation.
-
Influence of adsorbed particles on Streaming Potential of mica
Colloids and Surfaces A: Physicochemical and Engineering Aspects, 2001Co-Authors: Maria Zembala, Zbigniew Adamczyk, P. WarszyskiAbstract:Abstract Zeta Potential of natural mica covered by polystyrene and melamine latex particles, was determined by the Streaming Potential method. Measurements were carried out using the parallel-plate channel formed by two mica sheets separated by a teflon spacer. The dependence of Streaming Potential on surface coverage (reaching 0.45) was determined at pH 5.3, when the particles were positively charged and at pH 7.8, when the melamine particles became neutral. The coverage was determined directly by optical microscope counting procedure. It was found that the negative Streaming Potential for bare mica E s was significantly increased by the presence of adsorbed particles. The experimental data were interpreted in terms of a theoretical model postulating that the Streaming Potential change was due to flow damping over the interface and by charge transport from the double-layer surrounding adsorbed particles. In contrast to earlier approaches, no assumption of the slip (shear) plane shift upon particle adsorption was made. The experimental data allowed one to determine empirically the universal correction function, which can be exploited for quantitative measurements of bioparticle adsorption kinetics via the Streaming Potential method.
-
Measurements of Streaming Potential for Mica Covered by Colloid Particles
Langmuir, 2000Co-Authors: Maria Zembala And, Zbigniew AdamczykAbstract:The zeta Potentials of natural mica, bare and covered by positively charged latex particles of micrometer size range, were determined by the Streaming Potential method. Measurements were carried out using the parallel-plate channel formed by clamping together two mica sheets separated by a Teflon spacer. The dependence of Streaming Potential on surface coverage (ϑ) of adsorbed particles was determined for various ionic strengths and particle sizes. The coverage was determined directly by optical and electron microscope counting procedures. It was found that the negative Streaming Potential for bare mica Es was significantly increased by the presence of adsorbed particles. The dependence of the reduced Streaming Potential Esp/Es (where Esp is the zeta Potential in the presence of particles) on ϑ exhibited an universal behavior being independent of particle size and ionic strength. These experimental data were interpreted in terms of a theoretical model postulating that the Streaming Potential change was du...
Laurence Jouniaux - One of the best experts on this subject based on the ideXlab platform.
-
Saturation dependence of the Streaming Potential coefficient
2020Co-Authors: Laurence Jouniaux, V. Allègre, Renaud Toussaint, Fabio ZysermanAbstract:Observations of Streaming Potential for unsaturated conditions do not always show the same trend depending on the hydrodynamic conditions and because of a lake of coherency between the data processing procedures. We combine the data from three studies published in the literature, acquired during non-steady state drainage experiments, and apply the same processing steps. We model the hydrodynamic behaviour of these experiments to confirm that they experienced different flow dynamics. We argue that the raw SP data should not be corrected unless a clear drift of the electrodes stability is observed. The combined hydrodynamic behaviour and the Streaming Potential response show that (a) the observations of one of the experiment (exp #1) are associated to a limited range of water saturation (0.85-1). The corresponding signals could 16 therefore be fairly modelled assuming no saturation dependence of the SPC whatsoever; (b) the observations of exp #3 led to a SPC that can be larger than its value at saturation; (c) the observations of the exp #2 show a non-monotonous behaviour of the SPC as saturation decreases. The underlying physics of a non-monotonous SPC is related to water/air interfaces as shown by the results of the lattice Boltzmann numerical simulations. The main contribution to the SPC behaviour comes from the charged water/air interfaces and depends on the dynamic state of moving or entrapped bubbles. We finally describe the consequences of such a behaviour on the seismoelectric conversions for unsaturated conditions.
-
Influence of water pressure dynamics and fluid flow on the Streaming‐Potential response for unsaturated conditions
Geophysical Prospecting, 2015Co-Authors: V. Allègre, Laurence Jouniaux, François Lehmann, Pascal Sailhac, Renaud ToussaintAbstract:Streaming-Potentials are produced by electrokinetic effects in relation to fluid flow and are used for geophysical prospecting. The aim of this study is to model Streaming Potential measurements for unsaturated conditions using an empirical approach. A conceptual model is applied to Streaming Potential measurements obtained from two drainage experiments in sand. The Streaming Potential data presented here show a non-monotonous behaviour with increasing water saturation, following a pattern that cannot be predicted by existing models. A model involving quasi-static and dynamic components is proposed to reproduce the Streaming Potential measurements. The dynamic component is based on the first time derivative of the driving pore pressure. The influence of this component is investigated with respect to fluid velocity, which is very different between the two experiments. The results demonstrate that the dynamic component is predominant at the onset of drainage in experiments with the slowest water flow. On the other hand, its influence appears to vanish with increasing drainage velocity. Our results suggest that fluid flow and water distribution at the pore scale have an important influence on the Streaming Potential response for unsaturated conditions. We propose to explain this specific Streaming Potential response in terms of the behaviour of both rock/water interface and water/air interfaces created during desaturation processes. The water/air interfaces are negatively charged, as also observed in the case of water/rock interfaces. Both the surface area and the flow velocity across these interfaces are thought to contribute to the non-monotonous behaviour of the Streaming Potential coefficient as well as the variations in its amplitude. The non-monotonous behaviour of air/water interfaces created during the flow was highlighted as it was measured and modelled by studies published in the literature. The Streaming Potential coefficient can increase to about 10 to 40 when water saturation decreases. Such an increase is possible if the amount of water/air interfaces is increased in sufficient amount, which can be the case.
-
Influence of water pressure dynamics and fluid flow on the Streaming-Potential response for unsaturated conditions
Geophysical Prospecting, 2015Co-Authors: V. Allègre, Laurence Jouniaux, François Lehmann, Pascal Sailhac, Renaud ToussaintAbstract:A B S T R A C T Streaming-Potentials are produced by electrokinetic effects in relation to fluid flow and are used for geophysical prospecting. The aim of this study is to model Streaming Potential measurements for unsaturated conditions using an empirical approach. A conceptual model is applied to Streaming Potential measurements obtained from two drainage experiments in sand. The Streaming Potential data presented here show a non-monotonous behaviour with increasing water saturation, following a pattern that cannot be predicted by existing models. A model involving quasi-static and dynamic components is proposed to reproduce the Streaming Potential measurements. The dynamic component is based on the first time derivative of the driving pore pressure. The influence of this component is investigated with respect to fluid velocity, which is very different between the two experiments. The results demonstrate that the dynamic component is predominant at the onset of drainage in experiments with the slowest water flow. On the other hand, its influence appears to vanish with increasing drainage velocity. Our results suggest that fluid flow and water distribution at the pore scale have an important influence on the Streaming Potential response for unsat-urated conditions. We propose to explain this specific Streaming Potential response in terms of the behaviour of both rock/water interface and water/air interfaces created during desaturation processes. The water/air interfaces are negatively charged, as also observed in the case of water/rock interfaces. Both the surface area and the flow velocity across these interfaces are thought to contribute to the non-monotonous behaviour of the Streaming Potential coefficient as well as the variations in its amplitude. The non-monotonous behaviour of air/water interfaces created during the flow was highlighted as it was measured and modelled by studies published in the literature. The Streaming Potential coefficient can increase to about 10 to 40 when water saturation decreases. Such an increase is possible if the amount of water/air interfaces is increased in sufficient amount, which can be the case.
-
Streaming Potential of a sand column in partial saturations conditions
Journal of Geophysical Research, 2003Co-Authors: Xavier Guichet, Laurence Jouniaux, Jean-pierre PozziAbstract:The understanding of the Streaming Potential in partial water saturation conditions in porous media is of great interest for the interpretation of spontaneous polarization observations. We built a device which allows us to quantify the Streaming Potential at various saturation conditions using a sand column of 1-m height and 8-cm diameter. This is the first time that such a quantification has been performed. Different gases such as argon, nitrogen, and carbon dioxide are injected into the sand to decrease its water saturation, and to make the fluid flow within the sand. The measured electrokinetic coupling coefficient in partial saturation is either constant or decreases by a factor 3 with decreasing water saturation from 100 to 40%, whereas the sand electrical resistivity is enhanced by a factor of 5.
-
Streaming Potential in volcanic rocks from Mount Pelée
Journal of Geophysical Research, 2000Co-Authors: Laurence Jouniaux, Marie-lise Bernard, Maria Zamora, Jean-pierre PozziAbstract:Streaming Potential and electric conductivity have been measured in a laboratory on 11 consolidated samples coming from five deposits of the different evolutionary stages of Mount Pelde volcano. The Streaming Potential coupling coefficient ranges from-35 to-4905 mV MPa-1 and increases with increasing permeability. This increase is mainly due to the dependency of rock effective conductivity with permeability. The permeability of the samples varies from 0.146x10-12 to 34x10-12 m 2. The zeta Potential, at pH-7 and water conductivity of 2.1x10-4 S m-l• is relatively small for the majority of the samples. It ranges from-4 to-19 reV. According to water conductivity analysis on Mount Pel•e, Streaming Potential coupling coetficients of-25 to-406 mV MPa-1 can be expected for this volcano.
David Erickson - One of the best experts on this subject based on the ideXlab platform.
-
Streaming Potential and Streaming Current Methods for Characterizing Heterogeneous Solid Surfaces.
Journal of colloid and interface science, 2001Co-Authors: David EricksonAbstract:By monitoring changes in electrokinetic parameters, the Streaming Potential technique has been used as a method of characterizing heterogeneous surfaces, for example, due to protein adsorption. In general it is assumed that the change in the Streaming Potential is proportional to the degree of heterogeneity. In this study a simple model of the electrokinetic flow through heterogeneous slit channels has been developed with the goal of comparing the Streaming Potential and Streaming current techniques and determining under what conditions the aforementioned proportionality assumption will produce erroneous results. The flow simulations have shown that, when the Streaming Potential induces significant flow impedance, a severe deviation from the linear assumption is observed. Since Streaming current measurements are unaffected by electrokinetic flow effects, more consistent results are predicted and they are preferred for measurements made in small channels. Additionally it has been shown that the distribution of the heterogeneous coverage has a negligible effect on both the Streaming Potential and the Streaming current in cases where the double-layer overlap is not significant. Copyright 2001 Academic Press.
-
Streaming Potential and Streaming current methods for characterizing heterogeneous solid surfaces
Journal of Colloid and Interface Science, 2001Co-Authors: David EricksonAbstract:By monitoring changes in electrokinetic parameters, the Streaming Potential technique has been used as a method of characterizing heterogeneous surfaces, for example, due to protein adsorption. In general it is assumed that the change in the Streaming Potential is proportional to the degree of heterogeneity. In this study a simple model of the electrokinetic flow through heterogeneous slit channels has been developed with the goal of comparing the Streaming Potential and Streaming current techniques and determining under what conditions the aforementioned proportionality assumption will produce erroneous results. The flow simulations have shown that, when the Streaming Potential induces significant flow impedance, a severe deviation from the linear assumption is observed. Since Streaming current measurements are unaffected by electrokinetic flow effects, more consistent results are predicted and they are preferred for measurements made in small channels. Additionally it has been shown that the distribution of the heterogeneous coverage has a negligible effect on both the Streaming Potential and the Streaming current in cases where the double-layer overlap is not significant.