Once satisfied that an amplitude, as produced by the user's favorite migration process/algorithm, contains sufficiently accurate and interesting information, the use of that knowledge must be simple and enlightening. Herein I will introduce an AVA (or O if you insist) attribute that is easily calculated, quickly interpreted, and physically meaningful. This attribute will be derived from a different, though related, cross-plot that shows significant improvement over the classic Intercept-Gradient plane.
While it is clear that there are likely few geophysicists truly
excited about the introduction of yet another seismic attribute, I
believe that Shale-Normal Amplitude (SNA) analysis described herein can greatly ease
and quantify the interpretation of AVA data. The premise is very
simple and the output concise and enlightening. The attribute is
derived from a Compression-PseudoShear reflection coefficient
plane that allows significantly more insight into the lithologies at
depth than the traditional Intercept-Gradient (
) plane.