1. WinSism refraction seismic of W_GeoSoft Geo2X SA
How to use the software ?

2. Compatibiliy Window 7,8 (PDF display problem)
Window Xp (no known problem)
Windows 95, 98 (no known problem)
Windows 2000 & NT (Occasional compatibility problems)
Windows Me (Few feedback…)

3. Few abbreviations to know
TT= travel time
FBP= First break point
IT=Intercept times
BR=Bedrock
GRM= Generalized Reciprocal Method
SU=Seismic Unix

4. First you must convert your field data to SU format
Click here
Then select your file format

5. To convert SEG2 to SU, just select all records of a spread
Select your records
Convert to Su format
All shots data of one spread will be recorded into one large SU file !!!,
Shot order must be the same as field recording order,
shot 1 = first offset, shot 2=end shot 1

6. First break picking is the next step Precise picking is fundamental!
Select the SU file
Use the scroll bar to select record
Pick the FBP
(First break points)
You can enlarge trace size, clip amplitudes and more…
With the mouse reduce time display

7. How tu use automatic picking
First, click on the smallest break time with the right button
The move the scroll to adjust all FBP automatically
If necessary adjust parameters
Picking can be corrected later

8. Travel time structure
To give valuable informations a seismic refraction spread MUST have at least 2 offsets, 2 end shots one center shot (see REDPATH booklet) !
You can have up to 48 shots and 96 receivers per shot
Distance ZERO is END SHOT 1
Offset 1 will have a negative distance
All receiver distances are measured from END SHOT 1

9. Now, we can build the travel time (1)
You must enter few data
File name
Geophone spacing and number
Shot spacing and number

10. Build the travel time (2)
Double click on the top first cell of shot 1 and the select the corresponding FBP file.
Repeat for all shots
Time delay can be added to all times
FBP files can be renamed when used or reversed

11. Build the travel time (3)
Click on SAVE and DISPLAY
Repeat for all shot and correct if necessary shot location and elevation

12. Build the travel time (4)
Display and control the travel time
Zoom is possible

13. Travel time correction 1
Select and display the SU file
Click on the FPB to correct
Travel time is updated automatically
If necessary adjust display parameters

14. Travel time correction 2
Correct the value on the grid then click on SAVE and DISPLAY button

15. Travel time correction 3
You can move any FBP time, double click on a point, keep pressed and release the mouse at the new correct location.
To delete a point, double click on it and release without moving.

16. Bed rock velocity determination
To know the BR velocity use the true velocity between the two offset shots
If you have not a straight line, you can have more than one BR velocity
If you know the number of layers save the BR velocity

17. Travel time moving You can move the offset shot down to the End shot
Bedrock arrivals
You can determine:
Which part of the End shot belongs to bedrock
The intercept time for the end shot (Save it)
First and second layer arrivals

18. Velocity determination (1): Linear regression
Select a shot first and last geophone
Compute using linear regression and save the velocity for the correct layer number

19. Velocity determination (2)
You can draw a line with the mouse (Down, move Up), velocity is computed and can be saved
(Menu PROCESSING VELOCITY DETERMINATION)

20. Depth computation Intercept Time method
When all layer velocities and IT have been determined, you can compute the layer thicknesses and BR depth
Select shot
Compute
Save if not automatic

21. Coloured profile display (1)
Select the PROFILE PARAMETER tab
And enter your choices
Profile elevation and thickness
Draw shot or/and geophones
Click here to prepare the profile

22. Coloured profile display (2)
This graph can be saved as WMF, JPG file or copy into the clipboard and PASTE into any program (WORD, PAINT, CORELDRAW)
Click on right button to launch graph editor

23. ABC method (1)
Move down the offset travel time to fit as well as possible on the end shots

24. ABC method (2) Move the total time line down to the end of shots
You can now compute time from surface to bedrock below all geophones
Delay times give a good idea of bedrock geometry, like furrows

25. ABC method (3)
If you already compute depth below shots, you can know the bedrock depth below all receivers

26. ABC method (4)
You can also display a ABC coloured profile

27. GRM method (1)
This method is not suitable if you have less than 24 geophones
First have a look on the velocity fonction curve to select the receiver spacing
See the PALMER thesis PDF file in the W_GeoSoft CD-ROM for all theory

28. GRM method (2)
Then the Time depth curve is drawn

29. GRM method (3)
Last step, depth computation below all geophones and save the values in the GRM grid file

30. GRM method (4)
Using the GRM file, you can draw a coloured profile of GRM depth computation

31. Quick interpretation
You can have easily a first idea of depth with the QUICK INTERPRETATION module. The
Just select the shot number, the number of layer and move the layer limit
You can save depth and velocities in the WinSism WS4 file

32. WinSism menu
Most of the operations can be launched using pictograms or shortcuts
Thickness computation
Printing
Display profile
ABC method
GRM Method
Zoom
FB picking
Redisplay TT
File info
Correct a TT
Build TT
Quick interpretation
Trace moving
Velocity linear regression
Velocity point to point
Velocity line
True velocity
Help
Ruler
EXIT
Display a TT
Read a WinSism file
Save a WinSism file
Convert field records