Abstract: Let the Data Speak to You, or How to Improve Your 3-D Seismic Interpretation

BROWN, ALISTAIR R.
Consulting Reservoir Geophysicist, Dallas

There is no question about the success of 3-D seismic technology, but we can still do better. Much 3-D data remains underutilized, and some is strained beyond its limit by interpreters with unreasonable expectations. Three-D interpretation has become too popular for its own good--geoscientists and engineers are working on the data without adequate understanding of geophysical principles. In 2-D interpretation the seismic data added information to an existing geological model. In 3-D interpretation, we must let the data speak to us and try to believe it, modifying geological concepts if necessary.

It takes time to interpret 3-D seismic data, but we must use this time to maximum advantage. We must use all of the data without necessarily looking at it all. We must appreciate the precision of machine autotrackers, and investigate what part of that precision is geology and what part is noise. We must become familiar with unconventional displays. Faults don't have to be recognized on a vertical section to be valid! How long will it take for everyone to embrace color and discard those old wiggles?

There is a great need for the appreciation of geophysical principles. Seismic resolution is fundamental; we must know the magnitude of the seismic wavelength in order to appreciate the resolving power of our data. This determines the minimum thickness of flow units about which our engineers can discern information. We must correlate seismic to geology on character, not simply time, and be alert to phase distortion as we do so. Seismic attributes are wonderful, but they lack independence and should not be subject to too much statistics.

Let the data speak! 

AAPG Search and Discovery Article #90927@1999-2000 AAPG Distinguished Lectures