Geology Reference
In-Depth Information
c)
STC Coherence
a)
Waveforms from 3,764.89 ft
Compressional
wave
Shear
wave
Stoneley
wave
Slowness
µs/ft
40
340
13
12
11
10
9
8
7
6
5
4
3
2
1
1000
2000
3000
4000
5000
b)
3,760
300
200
100
1000
2000
3000
4000
5000
Time,
μ
s
3,770
Figure 8.42
Slowness-time-coherence processing of sonic waveforms. Slowness estimates are made by scanning sonic waveforms over time
windows and over a range of angles to maximise coherence; (a) waveforms at a particular depth, (b) coherence (red colour
¼
high coherence)
shown on time vs. slowness (
μ
s/ft) plot, (c) coherence shown on depth scale (after Haldorsen
et al
.,
2006
). Figure copyright Schlumberger.
Used with permission.
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