electro-acoustic coupling in porous oil-water two-phase systems: role of liquid micromenisci

T. S. Nguyen, L. Lefferts, K. SeshanCatalytic Processes and Materials, Faculty of Science & Technology

A. Imran, G. Brem, E. A. Bramer

Laboratory of Thermal Engineering, Faculty of Engineering Technology

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Correspondence: T.S.Nguyen@utwente.nl Green & Smart Process Technologies

Intro

UNIVERSITY OF TWENTE.

Electro-acoustic coupling in porous oil-water two-phase systems: Role of liquid micromenisci

Tarun Kumar, Helmut Rathgen, Frieder MugeleFOM-Shell IPP

Electro-seismic(ES) effect has become a hot topic in the exploration of oil and gas reservoirs in recent years. The effect can be defined as the generation of electrical potential in the subsurface by the passage of seismic waves. However, various aspects of the experiments are not well described by the current theory. One shortcoming of this theory is that it ignores the presence of liquid menisci at interfaces and within partially saturated porous media. The goal of this project is to analyze the role of liquid micro menisci in both the electro-seismic as well as in the inverse electro-seismic effect.

In depth Understanding of:

Mechanism of ES coupling in two-phase situations involving oil-water (or water-gas) micromenisci

Roles of meniscus shape and (de)pinning of contact lines for the observed non-linear ES coupling

Enhancing factors of ES coupling and weather exciting the micromenisci in a appropriate manner can make it more efficient

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Sound

well controlled porous geometry

LaserLaser

To Photo detector

Function generator/Am

plifier

Amplifier/CRO

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Fiber Interferometer Hydrophone

Acoustic-Electro CouplingAcoustically driven menisci results in oscillating dipoles at the interface e.g. Oscillating Electric Field. The resulting field ionize the Ag electrode, causing a net voltage generation

Electro-Acoustic CouplingMenisci can be drive by the applied AC Field due to the presence of loosely binds charges at the interface(Debye layer). The oscillating menisci emits pressure wave which can be detected using a Hydrophone

Low Pressure SensingSurface of the menisci along with porous media acts as a periodic microstructure giving a diffraction pattern. The curvature of the menisci is calculated by fitting the experimental data with a numerical model.

Dynamics of micromenisci under the effect of external pressure

Figure 5: Schematic of experiment

Laplace eq. at liquid interface (see Fig 2)

Pext=PLap =σκ (1)σ= surface tension of waterk= curvature of liquid menisci

To calculate k

Using a superhydrophobic 1D reflection grating (with known parameters) as porous media immersed in waterFor a fix value of pressure Intensities are recorded for wide range of Incidence angle for zero, -1 and +1 diffraction orderExperimental data is fitted with a numerical model to calculate curvature of liquid menisci k

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Detector

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laser

sample

Figure 7. verifying the Laplace equation: first curvature were obtained for each applied pressures and the Laplace pressure was calculated using eq. 1 and compared with applied pressure

Figure 6. Experimental data for a fixed external pressure fitted with a numerical model to calculate the corresponding curvature of liquid menisci

References:-

[1] Rathgen ; H. : ‘’ Super Hydrophobic surface: from Fluids mechanics to Optics ‘’ Dissertation, year 2008, University of Twente, The Netherlands

[2] M. G. Moharam, Drew A. Pommet, Eric B. Grann and T. K. Gaylord. Stable implementation of the rigorous coupled-wave analysis for surface-relief gratings enhanced transmittance matrix approach. J. Opt. Soc. Am. A 121077 (1995)*

Correspondence: tarun18kumar@gmail.com

Figure 1:Schematic of experimental set up