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Engine - 3D ZO-MF Old is the original implementation of the 3D Zero-Offset Multi-Focusing (ZO-MF) search engine. This module performs the core MF parameter search on 3D pre-stack seismic data, computing the Multi-Focusing wavefield parameters (vertical travel time, radius of normal curvature, and emergence angle) for each output bin. Results are written to a Multi-Focusing database file (.kdb) that serves as input for the Data Enhance modules in a subsequent regularization or interpolation step.
This module is deprecated. For new projects, use the current Engine - 3D ZO-MF module, which offers extended functionality including on-disk trace vector (TVOD) mode, a richer calculation area definition, and improved restart handling. This older version is retained for compatibility with existing workflows.
The engine reads 3D CMP-sorted seismic gathers (or an arbitrary 2D line) within a user-defined aperture around each output bin. It initializes the GMFEngine with the Multi-Focusing parameter table, optionally constrained by a velocity corridor picking file or a connected velocity picking item, and optionally uses a spatially-varying near-surface velocity map. Processing supports multi-threaded CPU execution and GPU acceleration. Already-calculated bins are automatically skipped, so the run can be safely restarted after interruption.
Connect the SEG-Y file handle that holds the pre-stack 3D seismic data to be processed. The data must be accessible in random-access mode; the engine reads sub-aperture super-gathers from the file for each output bin. This is a mandatory connection.
Connect the sorted trace headers index associated with the SEG-Y data. The index must be sorted as a 3D CMP gather; the module validates this at startup and returns an error if the sort order is incorrect. This index is used to efficiently locate traces within the aperture of each output bin without reading the entire file.
Connect the bin grid that describes the spatial geometry of the input seismic data. This grid defines the inline and crossline spacing of the raw data and is used to retrieve traces within the MF aperture for each output bin. The fold map and topography map of the input binning are displayed in the Input Binning vista group for quality control.
Optionally connect a 3D velocity picking item (G3DPickingItem) to constrain the MF parameter search with a velocity corridor. When connected, the picking is spatially interpolated (re-triangulated) onto the output bin grid and used to limit the search range of the MF engine. If both this item and the File with picking parameter are provided, the file takes priority. Leave disconnected to perform an unconstrained search.
Connect the Multi-Focusing quantization table item that defines all MF search parameters: the discrete parameter grid (travel times, emergence angles, curvatures), the aperture extents (inline and crossline), the correlation window, the main frequency, the minimum fold threshold, and the minimum Fresnel zone size. This is a mandatory connection and controls the full parameter search space. The aperture values in this table determine how many input traces are gathered around each output bin.
Optionally connect a spatial matrix (map) of Fresnel zone scaling factors. When provided, the aperture used to collect input traces for each output bin is multiplied by the corresponding factor at that bin location. This allows the effective aperture to vary spatially across the survey, for example to reduce aperture in areas of poor data quality or to honor structural boundaries. Leave disconnected to use a uniform aperture everywhere.
Optionally connect a spatially-varying near-surface velocity map. The MF engine uses this map to account for lateral velocity variations at the surface when computing the MF operator for each bin. If not connected, a constant near-surface velocity from the MF parameter table is assumed. Providing this map improves focusing quality in areas with significant topographic or near-surface velocity variations.
Path to an optional velocity corridor picking file (.corr). This file constrains the MF parameter search by defining upper and lower velocity bounds as a function of time, preventing the engine from searching in physically unreasonable regions of the MF parameter space. The corridor is loaded once before processing begins. If this field is left empty and no GMFPickingItem is connected, the search runs without a velocity corridor constraint.
This group contains the storage file and output binning parameters for 3D mode. Use this group when the output is a full 3D volume defined by a regular bin grid. Exactly one of the 3D group or the 2D group must be configured; setting both or neither will cause an error at execution time.
Path to the output Multi-Focusing database file (.kdb) for 3D mode. The engine writes computed MF parameters (wave collection and vertical parameters) for each processed bin into this database. If a .kdb file with the same name but different MF table parameters already exists, the software will prompt whether to overwrite it. Already-calculated bins found in an existing file are automatically skipped, enabling safe job restart. Set this field only when using the 3D group.
Connect the output bin grid (GBinGridItem) defining the regular inline/crossline grid on which MF parameters will be computed in 3D mode. The output grid may differ from the input binning grid, for example having a finer spacing for interpolation or a different coverage area. This item is required when the 3D storage file is set.
This group contains the storage file and geometry parameters for 2D (arbitrary line) mode. Use this group when the output is a single 2D seismic line defined by an arbitrary set of bin points rather than a full 3D grid. Exactly one of the 2D group or the 3D group must be configured.
Path to the output Multi-Focusing database file (.kdb) for 2D (arbitrary line) mode. Functions identically to Storage file 3D but uses the 2D storage driver. Set this field only when using the 2D group with an arbitrary line geometry.
Connect the bin point vector (GBinPointVectorItem) that defines the output positions along an arbitrary 2D line within the 3D dataset. Each bin point specifies the XY location where MF parameters will be computed. When this item is set, the input binning grid is used internally for the geometry extractor instead of the output binning. Required when using the 2D storage group.
This group controls how densely MF velocity analysis results are saved into the database for quality control and subsequent velocity picking. Storing every bin produces a large database; the inline and crossline decimation factors below allow you to reduce storage without affecting the main MF output.
Inline decimation factor for velocity analysis storage. A value of 5 (default) means that the detailed velocity analysis output is saved for every 5th inline. Set to 1 to save every inline; increase the value to reduce database size at the cost of lower velocity analysis resolution. Minimum value is 1.
Crossline decimation factor for velocity analysis storage. A value of 5 (default) means detailed velocity analysis output is saved for every 5th crossline. Works in combination with Each inLine to define a sparse grid of locations where velocity analysis data are stored. Minimum value is 1.
This group defines which output bins are processed during this run. Use it to restrict computation to a sub-area of the output grid, for example to process a region in priority or to rerun only a portion of the survey after editing. The Calculation area vista overlay shows all candidate bins graphically; use the Update calculation area custom action to refresh it after changing parameters.
The first inline number to include in the calculation. Set to -1 (default) to start from the first available inline in the output grid. Use a positive integer to restrict processing to a sub-area beginning at that inline number.
The last inline number to include in the calculation. Set to -1 (default) to process through the last available inline in the output grid. Use a positive integer to restrict processing to a sub-area ending at that inline number.
The first crossline number to include in the calculation. Set to -1 (default) to start from the first available crossline in the output grid. Use a positive integer to restrict the calculation area along the crossline direction.
The last crossline number to include in the calculation. Set to -1 (default) to process through the last available crossline in the output grid. Use a positive integer to restrict the calculation area along the crossline direction.
Controls how output bins are selected for processing within the inline/crossline bounds defined above. Two options are available:
Constant grid (default): processes every Nth inline and Mth crossline as defined by the Step along inLine and Step along xLine parameters, using the Calculation rule to combine the two step conditions. This is the standard choice for regular sub-sampling of the output grid.
Selection by min offset: selects output bins based on the minimum source-receiver offset available at each bin location. Bins with at least one trace closer than the Min offset calculation distance are selected. Use this mode to preferentially compute MF parameters where near-offset data are available, which produces higher-quality zero-offset estimates.
Maximum source-receiver offset (in meters) used to identify bins with near-offset data when Selection type is set to Selection by min offset. Default is 100000 m (effectively no limit). Reduce this value to select only bins covered by short-offset traces. Visible only when Selection type is Selection by min offset.
A merge radius (in meters) used to combine nearby selected bins into connected groups when Selection type is Selection by min offset. Default is 0 m (no merging). Increasing this value will fill in spatial gaps between isolated selected bins, producing a more continuous calculation area. Visible only when Selection type is Selection by min offset.
Target minimum distance (in meters) between selected output bin positions when using Selection by min offset mode. Default is 1000 m. This parameter controls spatial thinning of the selected bin set so that results are not clustered more densely than this distance. Visible only when Selection type is Selection by min offset.
Determines how the inline step and crossline step conditions are combined to select bins in Constant grid mode. Two options are available:
Logical AND (default): a bin is processed only if it falls on both an Nth inline AND an Mth crossline. This produces a sparse regular grid of processed bins.
Logical OR: a bin is processed if it falls on either an Nth inline OR an Mth crossline. This produces a cross-hatch pattern covering every selected inline and every selected crossline, resulting in more processed bins than Logical AND.
Visible only when Selection type is Constant grid.
Inline decimation step for the output calculation grid in Constant grid mode. Default is 1 (every inline). Set to a larger value to process only every Nth inline, reducing computation time. The MF database will contain results only at the sampled inlines; the Data Enhance module interpolates between them. Visible only when Selection type is Constant grid.
Crossline decimation step for the output calculation grid in Constant grid mode. Default is 1 (every crossline). Set to a larger value to process only every Mth crossline. Works together with Step along inLine and Calculation rule to define the subset of output bins that will be computed. Visible only when Selection type is Constant grid.
Start time (in seconds) of the time window within which MF parameters are searched. Default is 0 s. Set this value to skip shallow data that should not contribute to the MF analysis, for example to avoid surface-wave contamination or water-bottom multiples. The MF engine will not compute parameters for reflection events above this time.
End time (in seconds) of the time window within which MF parameters are searched. Default is 6 s. Set this value to limit processing to the depth of interest and avoid wasting computation time on deep noise-dominated data. The MF engine will not compute parameters for reflection events below this time.
The following fields are updated automatically during and after execution and are read-only. They provide a quick summary of how many bins were actually processed.
Sparse factor: the ratio of processed bins to total output bins. A value close to 1.0 means the full grid was processed; values below 1.0 reflect the effect of inline/crossline step decimation or min-offset selection.
Number of calculation bins: the total count of output bins that were selected for computation in this run. Use this value to estimate run time before starting execution.
Refreshes the Calculation area vista overlay to reflect the current combination of inline/crossline range, selection type, step, and calculation rule settings. Run this action after changing any Calculation area parameter to see which output bins will be processed before starting the full computation. The overlay shows all candidate bins in the map view; bins that already have data in the .kdb database and would be skipped on restart are also indicated.