I am a PhD student and I am trying to interpret the seismic reflection mapping in the attached files from the 1970's era. Would somebody be able to tell me what units the contours are in and how would I convert these to depth in feet.
Dear Dave Gardiner,
1) The unit contour of your maps is in milliseconds (ms). It is a classical 2D time-structure map, maybe from a common midpoint shooting acquisition.
2) The seismic lines are converted to depth, as you can see on the right side of my picture, attached, with a couple of observations. If you want to To convert from time in milliseconds to depth in meters or feet, refer to the velocity chart for each horizon of interest. The integrated depth map will be created by multiplying the time structure and average velocity of each geological interval. The result is a map that, by definition, ties every control point if you have a well/s guided by the seismic.
Please, let me know if you have other questions. Best regards, Mario
Many thanks for your reply Mario, I really appreciate it. Can you help me further please as I don't quite understand it. In your right diagram there are 5 horizons marked on the cross section at the bottom page with seismic velocity in inches/second for each horizon. My seismic isochron map must relate to one of these horizons but I'm not sure which one. It must however be in the range of 0 to 5000 ft. I'm assuming my formula will be DEPTH = (CONTOUR ISOCHRON) x AVE SEISMIC VELOCITY, e.g. (500 x 0.01) x7700 (v2) = 38,500ft which is unrealistic and as would be any of the 5 seismic velocities in the formula. What am I doing wrong please? I have attached another image, does this help in the explanation. I also have another posting that you may get a chance to look at.
Kind regards
Dave
Dear Dave, 1 second is equal to 1000 milliseconds. Note that rounding errors may occur due to that you must put in your formula: 500x0.001,
, so always check the results, 500 x 0.001 x 7700 ---> 3,850 ft.
I will help you with your other questions, Cheers, Mario
- Badges
- Science topic
- Similar topics
- Geoscience
- Atmospheric Sciences
- Climate Science
- Climate Change