Geoscience Reference
In-Depth Information
Detection of the saturation front - Tranmission test
2340
Saturation front
2360
Seismic
source
2380
E1
F1
2400
2340
2420
2360
2440
2380
50
100
150
200
Offset (m)
(a)
Electric potential at E1 (a.u.)
1
Coseismic ield
0.5
0
−0.5
Seismoelectric conversion
−1
−1.5
30
40
50
60
70
80
90
100
110
120
20
(b)
Time (ms)
Fluid pressure ield at saturation front, point F1 (a.u.)
1.5
1
0.5
0
−0.5
−1
−1.5
70
20
30
40
50
60
80
90
100
110
120
(c)
Time (ms)
Figure 6.9
Transmission experiment with the seismic source in Well A and the electrical receiver in Well B.
a)
Geometry of the
test.
b)
Time series for the electrical potential showing the seismoelectric conversion occurring at the interface and the coseismic
field.
c)
Fluid pressure field at a point located at the saturation front at the center of the Fresnel zone. (
See insert for color
representation of the figure
.)
wells. Figure 6.10f shows the resulting electrical potential
distribution at the time for which the seismic energy is
beamformed. This shows a very strong dipolar field
associated with the beamforming.
In Figure 6.11, we repeat this operation for a set of
scanning points located at the same depth that cross
the position of the saturation front. Our analysis shows
that the strongest seismoelectric conversion is located
at the position of the saturation front. Therefore, we
can conclude that the scanning of the reservoir could
be used to determine the position of the saturation front
and to monitor its progression over time.
