black is white!
Tom Fulton and John Parrish are to initiate a revision of the SEG’s polarity standard. This was last studied in the ‘70’s and led to an interesting idea – a compression is a white trough for airgun data, and a black peak for vibrator data! Some, including BP were seemingly never very comfortable with the early work and the whole issue is to be re-visited with the intent of defining the standard more clearly, and to ‘see how processing affects polarity.’ We wish them luck...
SEG-Y – revision I
This initiative, originally sponsored by the PESGB (see PDM Vol. 3 N° 2), started out as an attempt to harmonize current usage of the ubiquitous SEG standard. Draft N° 5 of the revision is will be available for comments on the SEG website (www.seg.org). Changes to the standard (which should be backwards-compatible with older versions) include a move to a byte-stream format, to allow for the use of disk and CD and extended EBCDIC headers.
SEG Website
The intent is to make all SEG formats freely available on the SEG website in the near future, and to include links to sister standards organizations such as the UKOOA.
Not Y2K compliant!
Both SEG-D and SEG-Y use the dreaded 2 digit date format. In the interests of compatibility there is no plan to change this. New SEG standards will be Y2K compliant. The view of the committee which looked into this issue was that Y2K was not an issue for seismic tape users. You might like to consider this statement carefully if you are using SEG-Y in an archive, there is probably a couple of weeks to re-tool by the time you are reading this!
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