How to easily update the binary header

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Update your binary header using Perl

The perl script has been written with a minimum of libraries and should run without modification under unix. Perl is fast, in less than a second, a hundred files can be checked. Here are the steps you need to follow.

• Download the program updatebin.pl If your processing sequence doesn't fit, send me (Eric) a request and I'll add your proposal!
• Edit the script for the following:
  • Edit #!/usr/global/bin/perl -Tw to the location of your perl compilier
• Make a list of files you want to check in the file junk and run the program!

Three different options can be accessed from the command line. You can overide the datum with a -d for datum, -v for replacement velocity and -t for the total number of traces. If you don't use the -t command the program will count the number of traces for you. This does take a bit of time. Here's how to run the program to set the datum to 0 (sea level), the replacement velocity to 3600 meters per second and to let the prgram count the total number of traces.

ls *sgy > junk
~ekeyser/perl/updatebin.pl  -d 0 -v 3600 

Datum=0
Vel=3600

Working on line 
P172685.BURNT_MALLIK_M3D.f-pstm.200507.ver.sgy P172685 BURNT_MALLIK_M3D

Input Binary Line Header
Reference Number = ""
Line Name =""

 SI         NS      FORMAT   sort_code  num_traces  START_X    START_Y    START_Z
4000       1250       1          4          60         0          0          0         
END_X     END_Y     END_Z     GEOMETRY    sxflag    encanaflag START_WIND END_WIND
0          0          0          3          91         100        0          0         
PEAK       AVE       RMS     TRACE_SORT   DATUM        VEL  MAX_ENSEMBLE AXIS_TRACE
0          0          0          0          0          0          0          1         
AXIS_LINE AXIS_TIME PHASE      GAIN     GAIN_EXP ROTATION      CT_1       CT_2       CT_3
2          3          0          0          1          0          0          0          0         


I found 20000 traces
Output Binary Line Header

Reference Number = "P172685"
Line Name ="BURNT_MALLIK_M3D"

 SI         NS      FORMAT   sort_code  num_traces  START_X    START_Y    START_Z
4000       1250       6          4          20000      0          0          0         
END_X     END_Y     END_Z     GEOMETRY    sxflag    encanaflag START_WIND END_WIND
0          0          0          3          92         100        0          0         
PEAK       AVE       RMS     TRACE_SORT   DATUM        VEL  MAX_ENSEMBLE AXIS_TRACE
0          0          0          0          0          3600       0          1         
AXIS_LINE AXIS_TIME PHASE      GAIN     GAIN_EXP ROTATION      CT_1       CT_2       CT_3
2          3          0          0          1          0          0          0          0         
fini -- 

Note the following corrections were made:

• The Reference number was updated using the first field of the external line name
• The line Name was updated using the second field of the external line name
• the Format code was changed from a 1 to the number 6 (CSEG IEEE 32 bit float)
• the SeisX format flag was changed from 91 to 92 (SeisX 4.0 format)
• The total number of traces was counted and placed in the header (the number 60 changed to 20,000)

You may find the following encana_v100_stack.fmt useful to manually edit the binary header with SeisX 4.0. Copy this file to your SeisX project. Here's what this data look likes from (General), (Segy File Viewer). Here's what the viewer looks like for the above data:

• SeisX 4.0 viewer
  • Data before
  • Data after
• SeisX 4.0 viewer using the encana_v100_stack.fmt template
  • Data before
  • Data after

Yes, you can manually make the changes to your segy file using the encana_v100_stack.fmt template but it's a whole lot faster and more accurate to use the perl script

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Site Owner: Eric Keyser
Last Updated: August 4, 2005