RODE format endorsed by SEG (November 1996)

A new method of storing any data type, but typically seismics, on any media has been officially given the stamp of approval by the SEG.

The September-October issue of Geophysics, the journal of the Society of Exploration Geophysics (SEG) includes the specifications for the new Record Oriented Data Encapsulation (RODE) format. This is intended to allow for the copying - remastering of old (legacy) data recorded in obsolete formats onto the new High Density Media (HDM), such as D2, D3 and NTR RODE will provide "a standard way of migrating old data into the new environment and allows new data to be recorded efficiently on new media using existing formats". The essential problem is that many of the older formats were reliant on now obsolete recording techniques, sometimes hardware dependent, such as very long tape blocks. While it is possible to reformat all these older formats to a more modern format such as SEG-Y, such a reformat adds a considerable overhead to the remastering process. Furthermore, there is always the chance that there will be data loss or corruption in a reformatting operation. so that conventional wisdom is to encapsulate the old data format

Well logging ancestry

The encapsulation process is designed simply to allow a future reader of the HDM to recover the legacy data in its native format onto a disk file. This also means that such data can be processed with legacy software, providing of course that such software has been maintained between times! RODE has its ancestry, not in seismic acquisition, but in well logging. Schlumberger's LIS and DLIS formats form the basis for the American Petroleum Institute's (API) Recommended Practice 66 (RP66) format (2) for the digital exchange of well data. RP 66 was intended to be a highly generalized format offering "a major opportunity to have just one standard exchange format for all oilfield data" . However, the first version of RP66 was deemed to be too well log specific and it is the version 2 of RP 66 that has been used as the basis of RODE.

Hard to read!

Eric Booth of RODE Consultants and co-author of the Geophysics paper presented the new standard at the PESGB Data Management Seminar. Booth described RODE as having a generic grammar and data dictionary allowing for self defining data, easily handling of arrays and with simple rules for the incorporation of textual information. According to Booth, RODE is easy to write, but difficult to read because of its flexibility. RODE is important as it is already in use in major transcription projects. It is also being taken up by POSC and Geoshare as a data exchange format. As RODE use increases it may eventually be used directly in data recording. The overhead of encapsulation may be outweighed by the facility it offers of for example encapsulating raw data with textual or even scanned images pertaining to the project and bundling them all into one file which should be future-proofed with respect to media and file system changes.