Apply a horizon-varying trace shift
In this workflow, we’ll use a combination of DUG-Insight processes to apply a horizon-varying trace shift.
Begin by calculating the difference between an initial and a target horizon and save in a trace header. The next stage applies this difference to the output volume, shifting the traces. It can be used to match traces along a particular horizon, such as tying the water bottom.
You will need:
- A horizon picked on the volume you wish to shift, e.g. WB_Initial
- A horizon you wish to shift the traces to, e.g. WB_Regional
The image below shows a volume with the water bottom picked in pink (WB_Initial). The blue horizon (WB_Regional) shows the regional water bottom picked from other data in the area.
I wish to shift the traces of my new data to match the regional water bottom.
1. In the Control Panel > Process tab, click the blue "+" icon and add a Header Maths process.
2. Select your input data Volume.
3. Input your shallower horizon as h1 and your deeper horizon as h2.
4. Choose an empty header location, for example 205 tcm. Use this as your storage location.
5. Use Formula: h1-h2.
Now you have stored the TWT difference between your initial and regional water bottom horizons as a trace header in your output volume Header Maths_Modified-tcm-header. Use this process volume as the input to a Trace Shift process and apply a variable shift that aligns your traces on the water bottom horizon.
1. In the Process tab, click the blue "+" button and add a Trace Shift process.
2. Select your Header Maths_Modified-tcm-header process volume as input.
3. Assign the shift from the 205 tcm header (or whichever header you chose to store your shift values) and set the shift scalar to -1.
4. Set an appropriate output Z range for your data.
5. Open your Trace Shift _WB process volume in section view and visually QC that your traces are now in the desired location.