Transect: Lithoprobe East

Processed By: Western Atlas International-Western Geophysical
Date Processed: January 1991

Line 5 Migrated Stack

Location: Lithoprobe East, Newfoundland
Shot Point: 725-64

No. Processing History Line 5
1 Format Conversion SEG-Y to WGC code 4; Data correlated in field

Record Length
18 s

Sample Interval
0.004 s
2 Geometry and Field Statics Yes
3 Zone Anomaly Processor (Z.A.P) Attenuate anomalous high amplitudes
4 Amplitude Compensation Geometric spreading using a regional velocity function
5 Deconvolution Minimum phase inverse filter

Autocorrelation:


Near Trace Start Time
1 s

Linear Start Time Velocity
5700 m/s

Stop Time
17.5 s

Number of Windows
4

Average Window Length
5 s; Overlap: 33 %

Prediction Distance
0.024 s

Operator Length
0.18 s

Pre-Whitening
0.1 %

Trace Balance Window
2-8 s
6 CRP Sort Crooked profile adjustment

Bin Width
1000 m
7 Residual Statics Yes

Surface Consistent Statics
Miser (automatic)

NMO Corrected
With 1 regional velocity function

Window
1-10.5 s

Maximum Shift
+/- 0.03 s

Shot and Receiver Statics
Corrections
Yes
8 Velocity Analysis Picked by lithoprobe personnel

Constant Stacks
Yes
9 Filter Surgical 25 Hz lo-cut filter

Offset/Time
(0 m: 0-0.7 s); (7415 m: 1.5-3 s)
10 Amplitude Equalization AGC

Window Length
1 s
11 NMO Corrections Yes
12 Mute Picked by lithoprobe personnel

First Break
Common offset stacks
13 Trim Statics Using noise attenuated stack as model

Window
1-8 s

Maximum Shift
+/- 0.012 s
14 Stack 60 fold; Applying trace weights based on correlation with external model
15 Signal Enhancement Random noise attenuation (RNA)
16 Trace Mix 3 trace

Weighting
1-2-1
17 Migration Finite difference

Velocity Field/Percent Stacking Velocity
(0 s: 100 %); (4 s: 100 %); (7 s: 90 %); (15 s: 80 %); (18 s: 80 %)
18 Adjacent Trace Sum Yes
19 Filter Time variant (filters interpolated between specified time zones)

Time/Frequency
(0.1 s: 20-56 Hz); (2 s: 14-56 Hz); (4 s: 8-56 Hz); (18 s: 8-56 Hz)

Slope
24/48 (DB/OCT)
20 Post-Filter Corrections Yes

Reflection Strength Gain
0-1.5 s
21 Amplitude Equalization RMS

Windows
(w#1: 0.125 s); (w#2: 0.25 s); (w#3: 0.5 s); (subsequent: 1 s)

Other Formats Processed Comments
Structure Stack Yes
DMO Stack No