The number of traces summed into the natural bin in a seismic survey.
We compute fold F according to the equation
and trace density T using:
using the following parameters:
- Maximum offset Xmax
- the maximum offset recorded in the patch. If this is not known, and you are more interested in the fold at a given depth, then use the target depth instead.
- Source line spacing, S
- the distance between source lines.
- Source interval, s
- the distance between the source points along the source lines.
- Receiver line spacing, R
- the distance between receiver lines.
- Receiver interval, r
- the distance between the receiver points (sometimes called 'stations') along the receiver lines.
Cooper suggests a high-level guide for selecting an appropriate trace density, depending on the imaging problem at hand (modified here, based on oil sands applications):
|< 6000||Not advisable|
|6000 to 18 000||For simple structure plays with good signal:noise|
|18 000 to 25 000||For stratigraphic and subtuning plays with good signal:noise|
|25 000 to 100 000||Increasing as signal:noise deteriorates, or as structural complexity increases|
|100 000 to 1 000 000||Expensive seismic for worst-case scenarios|
|> 1 000 000||Very expensive seismic for reservoir development and time-lapse applications|
- Cooper, N (2004), A world of reality: Designing land 3D programs for signal, noise, and prestack migration (Tutorial), The Leading Edge, October and December 2004.
- Fold* — Android app for computing fold and trace density
- The power of stack — blog post