Residual time phase corrections

In seismic processing sequence trim static is applied as post-migration gather conditioning: removing short-period deviation, hodograph flattening, improving stack image resolution and horizon continuity. g-Platform provides a Trim statics module for self-titled procedure.

Create a new workflow 0190-residual-time-phase-correction

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And add all necessary modules, connect all input and output data (trace headers, SEG-Y handlers):

1) Read seismic traces. Load seismic data set 0170-rmo

2) Sort traces. Here we need to sort seismic traces for Seismic loop, add Sort traces module and set CDP-OFFSET headers for sorting:

3) Seismic loop. Connect trace headers vector (Input sorted headers) from the Sort traces module output and seismic (Input SEG-Y data handle) from Read seismic traces.

4) Trim statics. module can be used inside Stack Imaging or Seismic loop modules in two main types: Constant time and Time variant.

In Constant time type we apply one static shift for each trace inside gather. Main parameters in this mode is:

•Max shift <ms> - max shift for static correction;

•Start time <ms> - start time for static correction;

•End time <ms> - end time for static correction;

•Massive cross-correlation approach (true or false) – default calculation use cross-correlation between each trace of gather and stack trace, massive cross-correlation approach use cross-correlation between each trace of gather with other traces; this method more intense but theoretically more precise;

•Solving method – Gauss-Seidel or Lsqr (least-squares);

•Remove deviations from trend detection (true or false) – remove median static deviation from static correction.

In Time variant type we apply multiple static shift for each trace inside gather correspond to windows for static correction. Main parameters in this mode is:

•Overlapping <ms> - overlapping between windows to prevent static glitches between adjacent windows;

•Massive cross-correlation approach (true or false) – default calculation use cross-correlation between each trace of gather and stack trace, massive cross-correlation approach use cross-correlation between each trace of gather with other traces; this method more intense but theoretically more precise;

•Solving method – Gauss-Seidel or Lsqr (least-squares);

•Remove deviations from trend detection (true or false) – remove median static deviation from static correction;

•Time variant – a table that allows you to set window borders and maximum shifts for them.

Execute the module and check the results: CIG gather before and after trim static. The changes are very minimal and the we can see them in the near traces. In the output, the reflectors are better aligned at the near offsets. It is advised to the user to test the trim statics thoroughly before getting into production. Trim statics may not produce the desired results at all times. It is up to the user's requirement.

5) Save seismic by gather. Define an output name 0180-residual-time-phase-gathers and execute processing for the entire data set:

Parameters:

If you have any questions, please send an e-mail to: support@geomage.com