Author: Mike Cline, T/X Resources
After I finished the earlier posting, “Shaded Relief Maps for Subtle Fault Detection“, it occured to me that there may also be an interest in map displays for stratigraphic interpretation. This posting, and the one that immediately follows, illustrates how various map types and parameters can affect a stratigraphic interpretation presentation.
In the first slide in the series below, an autopicked two-way time color-filled map, a channel-like feature can be seen in the upper left quadrant of the mapping area. As we will see in later illustrations, it is fortunate that this colorbar was used—the channel may not have been as evident with other colorbars, as it is in this display. However, other than the two bounding faults (areas with the black crosses, indicating the manually-interpreted faults), not a lot of other structural and/or stratigraphic detail is evident. You can tell that the channel is draped across a nose, located between the red, high area to the northwest, and a gray area southeast.
See the larger Adobe Reader pdf file.
Author: Mike Cline, T/X Resources
Now for the less effective channel map displays:
Initially, I had included this portion in the original posting, “Effective (and Less Effective) Channel Maps” (see above). However, after thinking about it a while, I decided that it was too long, so I broke it up into two postings.
See the larger Adobe Reader pdf file.
As I mentioned in part one, the Channel TWT Color-Filled Map in the first slide of this series of images, is not as definitive because of the poor choice of colorbars. The upthrown fault block colored in red, increases the time range of the colors so much that the middle fault block, where the channel is located, is almost entirely in the green colors. This is the cause for the loss of color contrast, leading to less definitive channel edges. A map’s “dynamic range” (the spread of the largest-to-smallest values) is a key consideration when deciding on a colorbar.
Author: Mike Cline, T/X Resources
How fortuitous! I received my version 8.2 update of SMT’s Kingdom software this afternoon, and just got it installed. One of the new features that has been added to this version of 2d/3dPAK, is the ability to display the Shaded Relief of a grid. So, I thought that this would be a good time to introduce the technique to those viewers not familiar with the general concept. However, since I haven’t had a chance to get completely familiar with this newest feature in the SMT software, the surface and map displays shown below were created in my normal work flow using Golden Software’s Surfer program. As time permits, I’ll try to review, and compare, SMT’s new feature.
What is a Shaded Relief display? It is a map view of an artificially illuminated 3D surface whereby shadows are cast by minor deflections in the surface (shadowed deflections are facing away from the illumination source). This type of map is an excellent way to highlight smaller faults which may not have been seen, or noticed, on the vertical seismic displays.
See the larger Adobe Reader pdf file.
Author: Mike Cline, T/X Resources
Did you know that you can improve the resolution of most seismic data with a data processing sequence known as Spectral Whitening (aka. Spectral Balancing)? What is Spectral Whitening? It’s nothing more than increasing the bandwidth, or frequency content, of a seismic data set. The increase of the higher frequencies (naturally filtered by the earth) allow the interpreter to resolve smaller features than would normally be observed.
See the larger Adobe Reader pdf file (four pages).
Author: Mike Cline, T/X Resources
Usually, color-filled maps are utilized for structure map presentations. Preference, or habit? If this applies to you, why not consider using a 3D shaded surface display, which transfers so much more information than a standard color-filled map, to display an interpreted horizon or gridded surface?
The animated display below compares an “overhead view” of a color-filled map, with a perspective view of a 3D shaded surface display. The black crosses on the color-filled map indicate where seismic faults were manually interpreted (at 500′ increments—or, every fifth inline and crossline in the 3D seismic survey).
See the larger Adobe Reader pdf file (two pages).
Author: Mike Cline, T/X Resources
Has this ever happend to you? Just as you are getting ready to plot a horizon/grid as a finished, color-filled map for an upcoming meeting (a short fuse of course), then you notice anomalous data ”spikes” and/or “black holes”, that really detract from the appearance (and credibility) of the map? Don’t feel too badly though, they aren’t always that obvious on most of these types of “flat” map displays—often seeming to appear out of nowhere.
To correct the map, you have to go through the tedious process of trying to find the bad data, fixing it, and then trying to recreate the display just as you had it earlier (with all of the same title block and scale info that you had before, but forgot to keep)? Arrgghhh……. There has got to be a better way!
See the VuPak animation (17MB Media Player avi file).
Note: The avi file is fairly large, so it will take some time before the animation starts.
Author: Mike Cline, T/X Resources
Since the first posting, I’ve gotten nothing but encouraging comments. Here are a few:
“Good work Mike.” (Michael M.)
“This is very interesting!” (David W.)
“Excellent idea.” (Teri B.)
“I think it’s a great idea.” (Sara V.)
“Works!” (Yvon H.)
“Wow! You did it.” (Mark C.)
“Thanks a lot for your blog, brilliant idea.” (Julien F.)
From the sound of it, visitors may be starting to realize the potential usefulness of the blog (at least I hope so), and how the old SMT User email forum might mesh with it. I also just checked my website stats, and the number of “hits” is up by orders of magnitude–so I know it has gotten some interest from viewers.