When everything is working…

July 28th, 2010

So last Thursday everything was looking pretty dismal. Seisworks has two display views. One is mapview which shows all the lines you upload as if you were looking at them from above. In my case this makes a pretty rough looking grid. The other is Seismic View which displays your data and allows you to pick your horizons. My lines were all showing up in mapview but were coming up as big white rectangles in Seismic View. A bit of a problem. I came in and had a stroke of genius or maybe just a sudden urge to try anything new to fix the problem. When we upload the data we have to select a value for the trace number and for the shot number I was using traceno and source respectively. Switching these two fixed everything. It doesn't make any sense but it was a hallejulah moment! I don't know why it plays a role especially since in my case these two values are identical but I was so happy it was working I didnt question it. 

The same day Beatrice and I realized that I had a problem with my mapview. All of my data was being displayed as staircases instead of smooth lines. This creates a problem when you're trying to pick a horizon because it lets a line cross another line twice which means the program thinks that place is in two places at once which doesnt make any sense. We originally thought it might be because we had decimated the data, taking only every 10th ping. So Monday I removed all the decimations but still had staircases. I began wondering if it was a problem with precision and so I increased the significant digits in the latitude and longitude files. Then spent another couple hours of help editing the GMT script  that converts the latitude and longitude to UTM coordinates until it also displayed another digit.  Sure enough much smoother, and for lack of a better word, prettier lines. 

Since then I've been going through each line and picking horizons and making sure they match up at every intersection. Its what Beatrice called "an exercise in patience". I couldn't agree more. Thank goodness for pandora, Itunes, grooveshark, and lunch breaks. 

Now my biggest problems are ensuring all my horizons line up. As seen in the pictue below this is not always as easy as it sounds...

Its a little bit hard to pick out the yellow. But the left screen shows one East-West line and the right screen shows an intersecting North-South line. On each the yellow horizontal line segment is where i placed the top of the eocene before comparing. then on the left screen seisworks plots my northsouth pick as a vertical line so i can see if it matches up with the eastwest pick. and vice versa on the right screen. clearly there are some huge differences and its hard to assume which one is more correct. Headbanging and snack breaks result.