Going for the RED is an approach used by older interpreters. But for red to indicate hydrocarbons (like this example), lots of things have to be true that were not considered a few years ago. The project used here lies off south Louisiana. It contains several “emergence / subsidence” cycles, with obvious angular disconformities. Current automatic mapping logic can’t begin to handle such complexity, and it is obvious that visual interpretation is sorely needed, especially if we have any hope of tracking the strike slip faults that probably provide much of the trapping. If this were a section of sonic well logs, we’d feel fairly safe in picking this strong event as a probable reservoir. We cannot say that about a normal section, for a host of reasons. Actually what we are looking at is a sonic log simulation from seismic data. For now I ask you to treat it as solid, since the initial point of this presentation is to illustrate how important visual interpretation is in a preliminary selection of areas of interest. Inside, I present “before and after” pairs that are set up for “toggling”. If you have never used this tool, it is worth a visit here all on its own. Toggling helps one visualize why integration flips the polarities to achieve a simulation of lithology. Multiple well log matches prove it is doing the right thing. The reasons for including these comparisons are first that they really please me, and second because it is important for you to look at the stratigraphy with some confidence that you are really seeing true lithology. Strike slip faults are caused by stretching of shallower beds reacting to deep plate movement (continental drift). They are a fact of life that is hard to deny. Because the movement is horizontal, there may be no vertical throw to facilitate picking. This means we need every ounce of resolution improvement we can get.

Sonic log from an early shale play, imposed on an ADAPS non-linear inversion (left) and on the integrated final result (right). On the log, low velocities peak to the left (red on the the display). Bed thickness is crucial to stratigraphic correlation, and correlation is the exploration geologist’s most essential tool. In reservoir work, tracking thickness is all-important. Matching sonic logs must be the ultimate goal. All inversions contain “spike guesses” from all interfaces. Unless one is able to resolve this mess in one’s mind, any inversion by itself does not provide attributes that are trustworthy. Any single interface value is dependent on both of the bounding bed velocities. In addition, a “red” from the top interface means one thing while one from the bottom means the opposite. Thus the need for integration. Of course I don’t think others can match the ADAPS non- linear inversion, but that is something else. Examination will show there is little “polarity” correlation between inversions (even mine) and the well log. One must be careful with polarities. Many observers just line up events without regard to color. Note point A where polarities are opposed (some would think this a match). While the integrated match is not perfect, it’s pretty good. Note how well the thickness agrees. As we continue with the older part of the show, be prepared to toggle. All versions of the same original data have been carefully aligned, so two fingers on two arrows is all you need to make an intelligent comparison. Spend some time on this learning experience. A

1 Direct reservoir detection - Where words fail, the well match here says it all. It proves we could have predicted the presence of this particular reservoir before the act of drilling. The project has several wells, and the matches are all quite good. No well data was used as input to our processes, but it is nice for it to illustrate my points. The stars identify what I consider a basal sand, sitting on one of several unconformities (angular disconformities that is). The ability of the system to simulate lithology was crucial in my own interpretation.

Here is well #3. It appears to be tapping below our basal sand (again identified by stars). It is interesting to note that it (the basal sand) has petered out here. This is a problem we should expect in “on-lapping” deposition. Again this is a good match, but not perfect.

A Unadulterated stack This is the raw stack on comparison #1. Please toggle with my optimized stack. Toggling hint – place one finger on the left arrow, and one on the right arrow and start playing,

A Optimized stack input Toggle back w raw Or with the final. Going back and forth here is where the time should be spent, as the integration logic rearranges computed interfaces to simulate lithology. Lobes will disappear as they get combined with their mates.

Back to input (the optimized stack) A Final result Final ADAPS result If this is your first time into the concept, your reaction might be one of disbelief when you see the shifting lobes. All I need to say here is that the well matches are not lying, and there is no way I could make them up. The fact that normal seismic sections don’t represent lithology is worth knowing.

YYYY straight stack Toggle with the optimized stack. But first notice where the arrow is pointing. Straight stack

The optimized stack You should notice glimpses of the basal sand to the right of the arrow. Of course this becomes the input to the inversion/integration logic. Toggle back to the simple. Or toggle with the final Optimized stack

Amazing if true – (and we sure think it is). What we see repeated in this toggle trio is a serious case of tuning and subsequent de- tuning. The basal sand we see here (which checks out on other lines) hardly shows up before NLI. Final inverted and integrated

toggle with the optimized stack. Straight stack Another example.

The optimized stack Again notice that the basal sand is visible now, before inversion. In particular, really look at the right-hand arrow. Toggle back to the simple. Or with the answer Optimized stack

Final inverted and integrated Toggle with the optimized stack.

In-line XX6 and cross-line 2900 I close the toggling session with a right angle intersect to show the merit of visualizing complex results. These were two completely separate runs, using the same parameters Of note here is the “bright spot” verification we get when the hydrocarbon indication fades down dip.. the fact that these two runs tie beautifully builds confidence in the total system. Click to start over and really toggle this time. Or here to repeat the last series. Or here to return to base. Or here to start strike slip discussion.