[OpendTect_Users] Importing digitized seismic images.

[Gordon MacMillan]

I've been in the business of vectorizing tiff images of seismic sections
since the early 90s and I'm always surprised by how little known this
technology is in the industry. This may be because most of the more advanced
software is developed in Europe, specifically Britain, by small companies
without global reach that are focussed, as we are, on services and
speculative projects, not software sales. 

There are many examples of the successful application of seismic
vectorizing, notably the large discoveries made in India in the 1990s by
Cairn Energy, who re-interpreted vectorized seismic data over acreage
abandoned by Shell. My company was heavily involved in that project.

It is important to be aware that not all of the software available is equal.
Most of it detects only the black peaks of each seismic trace and outputs a
series of square waves that are filtered to produce a semblance of seismic
data. I appreciate that this might suffice for some applications.

At the high-end are software packages that follow the waveform, tracking the
negative-going wiggle part of the trace as well as the in-filled peaks.

Clearly the output quality is constrained by the condition of the original
hard-copy section, the care with which it is scanned and the subsequent
processing of the image prior to vectorizing. It is also clear that the
dynamic range of the output cannot exceed the dynamic range recorded on the
hard copy.

If a good quality segy conversion is required, I would suggest that the job
is farmed out to a specialist contractor.

Gordon MacMillan
gmacmillan at canesis.net