Presented at Annual Dutch Chemical Society meeting (NWO-CW), Veldhoven, Netherlands, 15-17 Feb, 2010

1. T. S. Nguyen, L. Lefferts, K. Seshan
Catalytic Processes and Materials, Faculty of Science & Technology
A. Imran, G. Brem, E. A. Bramer
Laboratory of Thermal Engineering, Faculty of Engineering Technology
GOAL
DESIGN&DEVELOPMENT
RESULTSANDDISCUSSIONS
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 Mugele
FOM-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
`
`
Sound
well controlled porous
geometry
Laser
Laser
To
Photo
detector
Function
generator/Am
plifier
Amplifier/CRO
V
Fiber Interferometer
Hydrophone
Acoustic-Electro Coupling
Acoustically 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 Coupling
Menisci 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 Sensing
Surface 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 water
k= curvature of liquid menisci
To calculate k
Using a superhydrophobic 1D reflection grating (with known
parameters) as porous media immersed in water
For a fix value of pressure Intensities are recorded for wide
range of Incidence angle for zero, -1 and +1 diffraction order
Experimental data is fitted with a numerical model to
calculate curvature of liquid menisci k
Figure 2
Figure 3
Figure 4
Detector
y
laser
sam
ple
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