BEFORE AFTER Let’s start by examining this particular sonic log match. We have super-imposed it both on the input (before) and on the output (after). Some will think the match on the input looks pretty good. Unfortunately this highlights a bad problem in the industry, since the lobe polarities are almost all wrong (Our protocol is left for low velocity “red” and right for high velocity “blue”. If you look closely at the “after” match you will see the polarity correlation is almost perfect. Coefficient (inversion spike) integration simulates lithology, and that process is responsible for the improvement in resolution we see above. Establishing coefficient positions and amplitudes via advanced pattern recognition is our way of creating a stream of inverted data to feed our integration logic. This stream consists of reflection coefficients (spikes) from multiple interwoven primary events that emanate from the tops and bottoms of all the lithologic units overlapped by the down wave. The ability of the logic to integrate successfully is dependent on the quality of the inversion itself. The spikes are derivatives of the lithology in the same way individual well log velocities are derivatives of the sonic log. If you understand what I say in this last paragraph you have a grip on what might be the most serious problem in conventional seismic practice. The web is full of postings that try to make too much of individual primary events, not realizing that the attributes of the beds themselves are almost certainly different from that of the dominant interfaces.

BEFORE AFTER In this tough market, improving resolution through inversion and integration has become an end in itself. While I keep thinking that these results are so good that others surely will send me trial data, just looking at them and trying new examples from my old data base gives me enough satisfaction to keep trying. Here I ask that you stand back and really compare this before and after, noticing how the fault breaks the section into two geologically believable segments. Then go back and imagine trying to pick it on the input (before). From examples like this, I am convinced a large percentage of old interpretations should be redone. Now go back and look at the input section, remembering the explanation of the inter-twined events we are seeing. That complexity is bad enough when the stratigraphy is constant, but as we get into the pinch-out area the individual primary elements start to change their interference patterns. Going into the faulted zone the changes get even more drastic. As I said earlier, it is surprising how many experienced seismologists seem to ignore this problem. Inversion and integration make a surprising difference. The final lesson to be learned is the need for extensive visual interpretations in fault resolution. I have become convinced that strike slip (parallel) faulting is very common. Because of their parallel movement, they are very hard to track. Every ounce of resolution improvement is needed, and over-automated mapping procedures fall short because of their complexity.