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The Seismic distributed loop is an interactive gather-by-gather processing container designed for large 3D pre-stack datasets, with built-in support for distributed (remote cluster) execution. It reads sorted seismic gathers from disk, runs all modules placed inside the loop on each gather in sequence, and optionally writes the processed output to a new seismic file. The Sort Traces module must precede the Seismic distributed loop in the workflow to define the sort order.
The loop supports interactive quality control: the current gather can be displayed in real time as the job progresses. Modules added inside the loop using the Modules Inside option are automatically connected in sequence; the output gather of each module is passed as the input gather to the next. If a job stops before completion, it can be restarted from the last processed gather number using the First/Last seq. gather parameters combined with the Append write method.
The primary seismic data container connecting to the SEG-Y dataset to be processed. Connect to the output of the Open SEG-Y or Read seismic traces module.
The handle to the SEG-Y file from which gathers are read. This is connected to the output SEG-Y handle of the Open SEG-Y module.
The sorted gather index vector produced by the Sort Traces module. This defines the order in which gathers are read and processed.
An optional second SEG-Y data handle for workflows that require two input datasets processed simultaneously (e.g., adaptive subtraction of a modelled multiple dataset from the original data).
The sorted headers for the optional second input SEG-Y file, providing the gather index for the secondary data stream.
The full path and filename of the output seismic file (GSD format) to which processed gathers will be written. If a job is restarted after failure, use the Append write method and do not change this filename so that processed gathers are appended to the partially completed output.
Selects how input gathers are presented to the processing modules. Sorting reads gathers in the sort order defined by the Input sorted headers (requires a Sort Traces module). Free sorting reads traces without requiring pre-sorted headers, which is useful for unsorted or irregularly sampled datasets. Default: Sorting.
Displays the current value of the primary sort key (e.g., CMP number or shot number) for the gather being processed. This is a read-only display field updated during interactive execution.
Displays the current value of the secondary sort key (e.g., offset) for the gather being processed. This is a read-only display field updated during interactive execution.
The sequential index number of the gather currently being processed. During interactive mode this field updates in real time. If a job fails, note this number to determine the restart point.
The sequential gather number at which processing begins. The default value of 1 processes all gathers from the beginning. When restarting a failed job, set this to the gather number after the last successfully written gather.
The sequential gather number at which processing ends. Set this to the total number of gathers in the dataset to process all data. Reduce it to process only a subset of gathers (e.g., for testing).
The step size between successive gathers to be processed. The default value of 1 processes every gather. Set this to a larger value (e.g., 10) to process every tenth gather for a quick QC pass across the full dataset.
When checked (default), the gather counter increments automatically after each gather is processed, advancing to the next gather. When unchecked, the loop stays on the current gather until the user manually advances it. Uncheck this for manual step-through mode during interactive QC.
When checked, the processing job halts immediately if an error is encountered on any gather. When unchecked, the loop skips the failing gather and continues with the next one, which is useful in production mode to process the majority of gathers even when a small number of corrupted gathers exist.
The delay time (in milliseconds) between automatically advancing from one gather to the next in interactive playback (movie) mode. Increase this value to slow down the playback speed and allow more time to inspect each gather display.
When checked, clicking a point on the location map display immediately triggers processing of the gather at the clicked location. This enables rapid random-access navigation across the survey for interactive QC.
The spatial aperture (in number of neighbouring bins) used to create super-gathers by merging traces from adjacent CDPs. Super-gathers increase the fold per gather, which is useful for improving velocity analysis signal-to-noise ratio in sparse or noisy surveys.
Grid spacing parameters that define the bin grid geometry used when constructing super-gathers from neighbouring CDP locations.
The step size for the primary sort key (e.g., inline number) when advancing from gather to gather in interactive mode. Increasing this value jumps multiple lines per step.
The step size for the secondary sort key (e.g., crossline number) when advancing from gather to gather in interactive mode.
Parameters controlling spatial interpolation of processing parameters (such as filter coefficients or velocity values) across gathers. When enabled, parameter values are smoothly interpolated between control points as the loop advances from gather to gather.