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This module generates a regularized virtual 3D prestack geometry by creating synthetic source-receiver pairs for each CMP bin in the survey. For every bin, the module places the desired number of source-receiver pairs whose midpoint coincides exactly with that bin center, using random azimuth and offset distributions within a specified aperture ellipse. The resulting virtual geometry is midpoint-consistent: each bin receives the same nominal fold regardless of actual acquisition irregularities in the original survey.
The random geometry generation works by pre-computing a set of random source-receiver offset patterns (called random patterns in the Fast run group), where each pattern contains the desired number of source-receiver pairs scattered within the inline and crossline aperture limits. For each bin, one of these pre-computed patterns is selected randomly and translated so that all midpoints fall at the bin center. Sources and receivers that fall outside the fold-map boundary or topography grid are excluded. The output is a trace header collection that can be connected to the Geometry Application module to create a regularized prestack dataset suitable for 3D KPSTM, amplitude analysis, or noise attenuation workflows.
The 3D survey bin grid that defines the CMP bin layout, inline/crossline step sizes, and survey boundaries. The bin grid also provides the topography map (used to assign elevations to virtual source and receiver positions) and the fold map (used optionally to restrict geometry creation to bins with non-zero coverage). This input is required; the module iterates over every bin defined in the grid.
The target number of virtual traces (source-receiver pairs) to be created per CMP bin. This value defines the nominal fold of the regularized output geometry. Each bin will have exactly this many synthetic trace positions assigned to it, subject to topography and fold-map filtering. Set this to match the minimum fold you need for subsequent processing steps — for example, a value of 20 to 50 is typical for standard 3D KPSTM or noise attenuation workflows.
The maximum half-offset distance (in metres) of virtual source and receiver positions measured along the inline direction from the bin center (default: 2500 m, minimum: 0 m). Random source-receiver positions are drawn from within an ellipse whose semi-axis in the inline direction equals this value. Increasing the inline aperture allows longer offsets in the inline direction, improving deep illumination and velocity discrimination. Set this to be consistent with the maximum offset available in the real acquisition geometry.
The maximum half-offset distance (in metres) of virtual source and receiver positions measured along the crossline direction from the bin center (default: 9 999 999 m — effectively unlimited, minimum: 1 m). Together with the Inline aperture, this defines an elliptical offset aperture within which random source-receiver pairs are generated. To create a circular aperture, set both inline and crossline values equal. Set this to a realistic crossline offset limit to avoid placing virtual receivers far outside the actual survey footprint.
The minimum spatial separation (in metres) required between virtual source positions and between virtual receiver positions in the output trace collection (default: 20 m, minimum: 0 m). Source or receiver positions that are closer than this distance are merged into a single point, reducing the total number of unique source/receiver locations in the output geometry. Set this to a value comparable to the station spacing in the original survey to avoid creating unrealistically dense virtual source/receiver clusters.
Controls whether virtual source or receiver positions that fall outside the bin grid boundary are allowed in the output (default: enabled). When enabled, sources and receivers may be placed outside the defined bin grid area, which can increase fold for bins near the survey boundary by allowing positions beyond the grid edge. When disabled, only positions within the bin grid boundary are used; any position that falls outside is rejected and that trace pair is not created. Disable this option when you need to strictly confine the virtual geometry to the area covered by the survey.
A parameter group that controls whether virtual geometry is restricted to bins and positions that have real fold coverage in the original survey. When fold-based cutting is active, bins and source/receiver positions with zero fold in the survey fold map are excluded from the output, preventing the creation of virtual traces in areas that were never recorded.
When enabled (default), the fold map stored in the bin grid is used to exclude bins and virtual source/receiver positions that lie in zero-fold areas. Only bins with non-zero fold and source/receiver positions near valid fold areas (within the Max distance to valid bin tolerance) are included in the output. Disable this option if the fold map is not available or if you want to generate uniform geometry across the entire grid regardless of original fold coverage.
The maximum allowable distance (in metres) between a virtual source or receiver position and the nearest bin in the fold map that has non-zero fold (default: 0 m, minimum: 0 m). A value of 0 means that only positions that fall exactly within a bin that has fold are accepted. Increasing this value allows positions slightly outside the fold-covered area to be included, which can help maintain fold near the survey boundary. This parameter is only active when Cut off fold map is enabled.
A parameter group that controls the efficiency of the random pattern generation. Instead of generating a completely new set of random source-receiver positions for every single bin, the module pre-computes a finite set of random offset patterns and then reuses them across bins. This greatly accelerates processing for large surveys at the cost of some variability between bins.
When enabled (default), the module pre-generates the number of random patterns specified by the Number random patterns parameter and assigns one of them randomly to each bin. This reduces computation time significantly on large 3D surveys. When disabled, a single fixed pattern (one set of random positions) is generated and applied identically to every bin. Disable this option only when strict repeatability between bins is required, noting that the geometry will then be identical for all bins within a run.
The number of distinct random source-receiver offset patterns to pre-compute when the Use fast run option is enabled (default: 2000, minimum: 1, maximum: 70 042). Each bin in the survey is randomly assigned one of these patterns. A larger number of patterns gives more variety in the offset distributions across bins (reducing acquisition-like footprint in the regularized geometry) but requires more memory and preparation time. For most production surveys, values between 500 and 5000 give a good balance between geometry variety and computation time.
The output trace header collection defining the regularized virtual geometry. Each entry contains a virtual source position (X, Y, Z), a virtual receiver position (X, Y, Z), and the CMP bin assignment. This output is connected to the Geometry Application module to create the regularized prestack seismic dataset. The total number of traces in the output equals the number of valid bins multiplied by the Desired traces count per bin, minus any traces rejected by fold-map or topography filtering.
A read-only output reporting the value set for the Desired traces count parameter. This value is stored in the output item for informational purposes and can be referenced by downstream modules that need to know the intended per-bin fold of the regularized geometry.