Trim Statics

Description Flatten gathers (stretch/squeeze) guided by correlation
Module(s) Image Gather Processing, Gather Attributes
Requirements Volume
Related RMO Correction, Local Trace Alignment
Works with Gathers

The gather/record is cross-correlated over a sliding window against a pilot trace, to determine the shifts that best align the window. The pilot trace is generated by stacking part of the gather, or selecting from another volume.

The shifts can be smoothed, then output for further processing or directly applied to the gathers.  

Create a Trim Statics process

Create a Trace Padding process
  1. In the Process tab, click the blue "+" icon and select New Process.
  2. Select Trim Statics and type a name for the process.

Configure input and output

Create a Trace Padding process
  1. In the details panel, select the Volume to trim.
  2. Select the Output type:
    • Calculated shifts: Output the shifts to a volume
    • Traces with calculated shifts applied: Output corrected gathers with shifts applied

Select the pilot trace

Create a Trace Padding process
  1. Choose the Pilot trace to match:
    • a. Stack of near-offset traces:
      • Enter the number of traces to stack
      • Choose the source of offset values: Calculate from headers, or use the Offset header.
    • b. Input pilot traces from reference volume:
      • Pilot Volume Type:
        • Single trace per gather: Match a trace in the pilot volume. The pilot volume must contain a single trace per record (i.e. a stack).
        • Each 2D trace matched to a 3D trace via CMP X/Y: The pilot volume must be a 3D volume. Interpolate a pilot trace at the CMP X/Y of the first trace in each gather.  

Configure the sliding correlation window

Create a Trace Padding process
  1. Analysis window size (ms): The length of the correlation window
  2. Analysis window moveup (ms): Step size of the sliding window. If empty, the default step is one sample.
  3. # of shifts to test (half window): The half-window number of shifts to correlate. The total number is 2N+1, e.g. for a value of 10, test 10 positive shifts, 10 negative shifts and the no-shift case.

Set the interval to update

Create a Trace Padding process
  1. Start time/End time: Enter the time extent to apply the static correction to
    • Enter time values, or choose horizons
    • Ramps are centred at the start/end time
    • The shift values are scaled to zero at the end of the ramps.

Smoothing Settings

Create a Trace Padding process
  1. Smooth shifts in lateral direction: Enable to smooth shifts across the gather
  2. Smooth shifts in vertical direction: Enable to smooth shifts vertically
  3. Smoothing order:
    • 0 applies no smoothing
    • Large values flatten the shifts
    • Tip: Try ~1/3 the number of traces per gather