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VSP
Recording Parameters:
P-wave
and S-wave vertical seismic profiles were
recorded by ESRI-University of South
Carolina in three wells at the 200 West
Area, USDOE Hanford Site in January 1999.
For P-wave acquisition a vertical steel
cylinder was placed on the ground and struck
six times. Each hit was vertically summed to
the preceding record in the seismograph and
written to disk as a single record for each
level. For S-wave acquisition strike plates
were mounted on the ends of a 8 ft.
horizontal plank and a truck driven on the
plank to couple the plank to the ground.
Each end of the plank was stuck six times,
first from on side of the vehicle and then
the other. The summed records for each
source orientation were written to disk
separately for each level.
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Raw
VSP well 299-W15-32. P-wave left,
S-wave right. BP 30-150 Hz
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Interval
and average P-wave velocity profile
well 299-W15-32
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Well
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299-W15-32
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299-W15-82
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299-W15-217
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Recorded
depth P wave
(m from TOC) |
1-71,
2-71
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1-22
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2-36
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Recorded
depth S wave
(m from TOC) |
2-71
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1-22
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2-36
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Source
offset P wave (m)
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6,
10.03
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5.55
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6.0
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Source
offset S wave (m)
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10
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6.0
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6.06
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No.
of hits P-wave, S-wave
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6,
6, (6,6)
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6,
(6,6)
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6,
(6,6)
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Depth
increment (m)
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1
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1
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1
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Sample
rate (ms)
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0.125
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0.125
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0.125
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Record
length (ms)
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1024
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1024
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1024
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VSP
Data Processing Flow:
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- Sort
field records / Reverse &
sum shear wave records
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- Write
depth info to headers
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- Display
/ Trace edits / Bandpass filter
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- Correct
times for source offset (TVT) /
Calculate velocity profile
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- Time
align downward travelling energy
/ Mean amplitude scaling
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- Spatial
median filter 5 pt - enhance
downgoing wavefield
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- Wavefield
separation (subtract median
filtered data from input)
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(Downgoing
waves)
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<------------------------>
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(Upgoing
waves)
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- Spiking
decon operator found
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- Bandpass
filter / Scaling
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- Bandpass
filter / Scaling
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- Align
at two-way reflection time
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- Spatial
median filter (5 pt)
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- Mute
/ Front corridor stack
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- Bandpass
filter / Scaling
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