Trace Shift

Description Apply a shift to each trace according to a header value or a constant.
Module(s) Explorationist, Image Gather Processing
Requirements Volume
Related Trace Padding, NaN Removal, Header Maths
Works with 2D, Stacks, Gathers


This process shifts each trace in TWT according to the value in a specified trace header. The shift amount can optionally be scaled by a multiplier and adjusted by a constant.

For each trace, the amount to shift is:

	Header * Scalar + Constant

This value will be interpreted as a shift in milliseconds, with a positive value moving the trace deeper (i.e. to a larger TWT).

The process uses sinc interpolation to apply shifts that are not a multiple of the sample interval.

Workflow

  1. In the Process tab, click the Add icon and select New Process.
  2. Select Trace Shift and type a name for the process.
  1. Select the volume to be shifted.
  2. Choose to shift by a Constant amount or Trace Header to calculate the shift from a header value.
  3. The amount of shift to apply (TWT) in milliseconds. Positive values shift traces deeper (increasing TWT).
    • If Constant was selected, enter the shift value
    • If Trace Header was selected, select the SEG-Y header containing the value from the drop-down list.
    • Enter a scalar value if required. For header values in milliseconds, use a scalar of ±1 (the sign depends on the header).
    • Enter a constant value to add to the scaled header value. The default is empty / no additional constant.
  4. Enter start and end times for the output traces. Output traces use the same sample interval as the input.

Notes:

  • This example applies a positive shift in milliseconds using the value stored in the "105 laga" header.
  • For header values containing microsecond data (e.g. TCM), apply a scalar of ±0.001 to convert the shift to milliseconds.
  • To apply shifts based on horizons, use Header Maths to load horizon values into trace headers.