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Engine - 2D CO-MF performs the Multi-Focusing (MF) search engine computation for 2D seismic data in Common Offset (CO) mode. For each virtual CO-class bin defined in the associated virtual geometry, the engine searches through the parametrization table of MF operators to find the optimal focusing parameters — the wave curvature and wavefront attributes that best align and stack the contributing traces from the surrounding aperture. The optimal MF parameters and the corresponding time-corrected wavefield events are written to a binary database file (.kdb) for subsequent use by the imaging and data enhancement modules.
The calculation can be run locally on CPU or GPU hardware, or distributed across a remote cluster using CPU or GPU nodes, making it suitable for both workstation testing and production-scale 2D surveys. The input seismic data must already be binned before running the engine — additional binning after the MF search would corrupt the geometry assumed by the downstream data enhancement procedures.
The engine supports restart: bins that have already been computed in a previous run are detected automatically and skipped, so interrupted jobs can be resumed without recalculating finished work. If the existing database was created with different parameters, the module prompts the user to cancel, continue with the old parameters, or overwrite the database entirely.
Path to the output .kdb database file where the engine writes the computed Multi-Focusing parameters and time-corrected wavefield events. This file is created (or opened) at the start of execution and is incrementally updated as each bin is processed. Specify a filename on a fast local or network drive with sufficient storage capacity for your survey. The file is used as direct input by the Data Enhance and Imaging CO-MF procedures that follow in the workflow.
Optional connection to a velocity constraint picking item produced by another procedure (for example, a velocity analysis or a previous MF run). When connected, this item defines a velocity corridor that restricts the MF parameter search to a geologically plausible velocity range at each time sample and spatial location. Using a velocity constraint can significantly reduce computation time and suppress spurious solutions in noisy data. If neither this item nor the File with picking parameter is specified, the search is performed over all velocities defined in the MF Tables Parametrization.
Connection to the input seismic dataset in SEG-Y format. This is the pre-stack 2D data on which the Multi-Focusing engine operates. The data must already be binned and should not be re-binned after this step. The engine reads traces from this handle on demand for each processing aperture, so the SEG-Y file must remain accessible throughout the entire run.
Connection to the sorted trace header index for the input SEG-Y data. This index tells the engine how traces in the SEG-Y file map to CDP, source, receiver, and offset positions. It is used to assemble the super-gather of all traces that fall within the spatial aperture around each processing bin. Typically provided by the output of a Binning or Header Sort procedure applied to the same dataset.
Connection to the virtual geometry item produced by the Virtual geometry COMF 2D procedure. The virtual geometry divides each CDP into a set of Common Offset classes, each represented as a virtual bin. The engine processes one virtual CO-class bin at a time, selecting real input traces whose midpoints and offsets fall within the CO aperture around that virtual bin. This item defines both the list of bins to be computed and their spatial coordinates.
Connection to the MF parametrization table that defines the discrete search space for the Multi-Focusing engine. The table specifies the set of velocity and wavefront-curvature values to test at each time sample, the time sampling grid, the spatial apertures for inline and crossline directions, the maximum offset, the correlation window length, the minimum fold threshold, the dominant frequency, and the minimum Fresnel zone radius. All of these engine-internal parameters originate from this item; only the spatial aperture and time range can be overridden by the user parameters below.
Optional connection to a 2D map (GMatrixItem) of near-surface or replacement velocity V0. When provided, this spatially variable V0 map is used by the MF engine to account for lateral variations in near-surface conditions when computing the MF operators. If not connected, the engine uses a constant V0 value defined in the MF Tables Parametrization. Connect this input when the survey area has significant surface topography or near-surface velocity contrasts.
Path to an ASCII velocity corridor file (.corr) that constrains the MF parameter search to a geologically meaningful velocity range. The file defines upper and lower velocity bounds as a function of time for one or more spatial locations. The engine interpolates the corridor spatially and restricts its search to parameter combinations that fall within the corridor bounds at each time and location. This is an alternative to the GMFPickingItem connector — if both are provided, the connector takes precedence. If neither is specified, the full velocity range from the MF Tables Parametrization is searched. Using a corridor is strongly recommended for production runs to reduce computation time and suppress noise-driven false solutions.
The spatial search radius (in metres) used to select real input traces that contribute to the MF operator at each virtual CO-class bin. The engine gathers all traces whose midpoints (or source-receiver pairs, depending on the aperture mode) lie within this distance of the virtual bin centre. Larger values include more traces in each operator, improving stack quality and signal-to-noise ratio, but increase computation time. The value should typically be set to somewhat larger than half the offset-class separation defined in the virtual geometry — for example, if offset classes are separated by 200 m, a value of 250–300 m is appropriate. Default: 250 m.
Controls how the CO Aperture distance is measured when selecting traces for each virtual bin. Two options are available:
XY aperture (default) — traces are selected if their CMP midpoint lies within the specified distance of the virtual bin in the horizontal XY plane, regardless of offset. This mode is suitable for most 2D land surveys with regular geometry.
Offset aperture — traces are selected based on the proximity of both the source and receiver positions to the virtual bin, constrained jointly by CMP distance and offset distance. Use this mode when the geometry is irregular or when you need tighter control over which traces are included in a given CO class.
When enabled, the XY aperture trace selection applies an additional azimuth constraint, restricting the contributing traces to those whose source-receiver azimuth aligns with the inline direction of the 2D line. This can help suppress cross-dip noise from scattered energy or from adjacent lines in crooked-line surveys. Default: disabled (all azimuths accepted within the XY radius). Only relevant when CO aperture mode is set to XY aperture.
This group controls how the computed MF results are compressed and periodically flushed to the database file during the run.
An integer compression level applied to the MF parameter data before writing it to the .kdb database. Higher values produce smaller database files at the cost of slightly reduced precision in the stored wavefield parameters. The value must be a positive integer. Default: 5. Use lower values (for example, 1–3) when maximum fidelity is needed for downstream amplitude-sensitive processing; use higher values (7–10) to conserve disk space on large surveys.
Controls how frequently (in number of bins processed) the engine flushes computed results from memory to the .kdb file. The default value of -65550 means results are saved continuously as each chunk is completed. Setting a positive integer N causes the engine to accumulate results for N bins before writing a batch to disk, which can improve I/O performance on slow network storage at the cost of potentially losing more work if the process is interrupted. In most cases the default is appropriate.
This group restricts the computation to a subset of bins and a time range within the dataset. Use it to test the engine on a small area before committing to a full survey run, or to reprocess only a specific zone after geometry or parameter changes.
The sequential index of the first virtual bin to process. Bins are numbered starting from 1 in the order they appear in the virtual geometry. Set to -1 (default) to start from the very first bin in the dataset. Use a positive value to skip the initial portion of the line — for example, to resume from a specific position or to process only a test segment.
The sequential index of the last virtual bin to process. Set to -1 (default) to process through the final bin in the dataset. Set to a positive integer to stop the computation at a specific bin. The value must be greater than or equal to First bin to calc; an error is raised if Last bin is less than First bin.
The stride between consecutively processed bins within the calculation range. Default: 1 (every bin is computed). Set to 2 to process every second bin, 5 to process every fifth bin, and so on. Use a larger step for rapid QC tests or sensitivity analyses where a sparse result is acceptable. The full dense database should use a step of 1.
When enabled (default: true), the engine automatically sets the First Time and Last Time values from the time range defined in the connected MF Tables Parametrization item. This ensures that the computation covers exactly the time range for which MF operators have been tabulated. Disable this option only when you need to restrict processing to a shorter time window — for example, to focus computation on a target interval and skip deep or shallow zones that are not of interest.
The start of the time interval (in seconds) over which the MF engine computes optimal focusing parameters. Samples earlier than this time are not processed. When Automatic time determination is enabled, this value is set automatically from the MF Tables Parametrization and should not be edited manually. Default: 0 s. Only relevant when Automatic time determination is disabled.
The end of the time interval (in seconds) over which the MF engine computes optimal focusing parameters. Samples later than this time are not processed. When Automatic time determination is enabled, this value is set automatically from the MF Tables Parametrization. Default: 6 s. Only relevant when Automatic time determination is disabled. Reducing this value to match the deepest reflector of interest can substantially shorten computation time on surveys with long recording windows.