4.3.11.1 SEG-Y

SEG-Y is the standard way to share volumes/lines of data. In OpendTect the files are loaded with a rigorous respect to the SEG standards using one of the two wizards:

• new SEG-Y wizard introduced in OpendTect 6.2
• Classic SEG-Y Import Tool (used to be the main utility for import of SEG-Y data prior to OpendTect 6.2)

Most SEG-Y files will be imported in a few clicks, and a number of exceptions can be set to load the most problematic data. Nevertheless there are a few guidelines that must be honored:

• The traces must be sorted either by inlines and then crosslines or by crosslines and then inlines.
• The gathers of prestack data must be consecutive and ordered by increasing offset (i.e. no common offset sorting).
• Inlines/crosslines or coordinates (and offset) must be written in every single trace header. Separate navigation data is only supported for 2D lines.
• The traces must have a fixed length.
• There is no support of extended textual headers.

Once the above criteria are respected, you will then enjoy a large freedom:

• Gaps can be present.
• The traces can start at any time/depth, even negative.
• The files can be merged during import, re-scaled using linear equations, and the storage format can be changed.

Please, read the entire chapter before asking for support. If you need support, please send us screenshots of each step and (of possible) a scan report together with a detailed description of your problem.