Active Source Data Format Standards & Futures

Stewart A. LevinConsulting Associate Faculty

Dept. Geophysics, Stanford Univ.

Differentiation

• Field recording– SEG-D (E&P seismic)– SEG-2 (Engineering seismic)

• Exchange– SEG-Y and near variants (SU)– Sometimes SEG-2 or SAC

• Processing– SAC, SU, SEP, Madagascar, commercial vendors– HDF

Status

• Field recording– SEG-D 3.0• Very comprehensive• GPS time stamps• Continuous recording

– SEG-2• Very flexible• Limited to 2 Gb per file• Microseismic community update effort(s)

Status

• Exchange– SEG-Y 1.0• Heavily (ab)used, some painful limitations• New draft version 2.0 being circulated

– supports multiple headers, long traces, header remapping, arbitrary sample interval, …

– SEG-2• No current effort to overcome 2Gb, but has been done

informally

– Various processing formats used when standards are too limiting or too complicated

Status

• Processing– No formal standards, a number of de facto options• SEG-Y flavors, SAC

– SEG has licensed HDF for use with its formats

Encapsulation

• Efficiency– Large tape records– Fixed length blocking

• Completeness– Assemble related meta-data, e.g. navigation,

observer’s notes, etc., with seismic– ZIP, tar, cpio don’t handle industry-sized seismic

files

Encapsulation

• Efficiency– SEG-D and SEG-Y have primitive blocking scheme– RODE overly complex for this purpose

• Completeness– No widely accepted options– One of the reasons SEG wants to use HDF