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Note: This module is deprecated. For current surface-consistent statics workflows, use the Geomage Surface Consistent Statics EXT module instead.
This module computes surface-consistent static corrections by decomposing trace time-shifts into independent contributions from shot locations, receiver locations, and CMP bins. It works by cross-correlating pairs of traces within a spatial aperture centered on each CMP, estimating the inter-trace time-shift that maximizes correlation, and then solving a surface-consistent least-squares system to separate the shot, receiver, and CMP components of those shifts. The result is a set of static corrections that can be applied to improve stack quality and alignment of seismic reflections.
The computation proceeds in multiple outer iterations (controlled by Number of iterations), where each iteration re-estimates trace shifts using the current static solution to align traces before cross-correlation. An optional coarsening outer loop (CO Outer iterations) starts with a large spatial aperture for the shot-receiver correlation window and progressively shrinks it by a factor each pass, allowing the solution to converge from a global estimate to a local one. Both 2D and 3D survey geometries are supported.
The SEG-Y dataset from which seismic traces are read. This handle provides access to trace amplitudes and sample timing information used to perform cross-correlations. The dataset must already be sorted and contain valid trace headers including source, receiver, and CMP coordinates.
The gather index describing the survey geometry — the mapping of traces to their CMP bins, sources, and receivers. This item must contain a valid 2D or 3D CMP geometry. It is used to define which traces belong to each CMP and to locate neighboring CMPs within the spatial aperture for super-gather construction.
The number of main solution iterations performed per coarsening pass. In each iteration, inter-trace cross-correlations are computed within the current spatial aperture, a new set of time-shift observations is collected, and the surface-consistent linear system is solved to update the static estimates. Increasing this value gives the solution more passes to converge but increases computation time. Default: 1. Minimum: 1. For most datasets 3–10 iterations are sufficient; use more when initial near-surface velocity anomalies are severe.
The number of internal iterations used by the least-squares solver when decomposing the observed trace time-shifts into shot, receiver, and CMP static components. Higher values allow the solver to converge to a more accurate decomposition. Default: 100. Minimum: 1. In most cases the default of 100 is sufficient for full convergence of the linear system.
The number of sub-iterations performed within each CMP super-gather when estimating inter-trace time-shifts by cross-correlation. Multiple sub-iterations refine the shift estimate by re-aligning traces with the current partial static solution before recomputing correlations. Default: 1. Minimum: 1. Increasing this value can improve shift accuracy when there is significant residual misalignment within a gather.
The maximum allowable time-shift (in seconds) that can be estimated between any pair of traces during cross-correlation. This value sets the search window half-width for the correlation peak. Set this to the largest expected static anomaly in the survey area. Values that are too small will miss large anomalies; values that are too large increase computation time and may pick spurious correlation peaks. Default: 0.032 s (32 ms). Minimum: 1 sample. Typical range: 0.016–0.128 s depending on near-surface conditions.
The start of the time window (in seconds) used for cross-correlation. Samples before this time are zeroed out before correlations are computed, so the statics solution is driven only by the reflection signal within the specified window. Set this to exclude the direct wave, refraction, or noisy shallow arrivals. Default: -1 (use the full trace from the first sample). Set a positive value to restrict the correlation to a specific reflection interval.
The end of the time window (in seconds) used for cross-correlation. Samples after this time are zeroed out before correlations are computed. Use this together with StartTime to isolate the reflection interval most useful for statics estimation, avoiding deep multiples or noise. Default: -1 (use the full trace to the last sample).
The half-aperture in the crossline direction (in crossline bin units) used to build the super-gather around each CMP. All CMP bins within this distance from the central bin in the crossline direction are merged into the super-gather before cross-correlations are computed. Larger apertures provide more traces and better statistical robustness but increase computation time. Default: 5 crossline bins. Minimum: 0 (use only the central CMP). For 2D surveys this parameter is unused.
The half-aperture in the inline direction (in inline bin units) used to build the super-gather around each CMP. All CMP bins within this distance from the central bin in the inline direction are included in the super-gather. Larger apertures include more traces and improve the signal-to-noise ratio of the correlation but may blur statics over lateral heterogeneities. Default: 5 inline bins. Minimum: 0. For 2D surveys this defines the half-width of the CMP aperture along the line.
The number of coarsening outer passes. In each pass the algorithm runs the full set of main iterations (Number of iterations) with the current shot-receiver aperture, then multiplies the aperture by CO Iteration Factor for the next pass. Starting with a large aperture captures long-wavelength static trends; successive passes with a shrinking aperture refine the short-wavelength component. Default: 1 (no coarsening — single pass). Set to values greater than 1 when you want a multi-scale approach.
The initial maximum shot-receiver distance (in metres) used to select trace pairs for cross-correlation within each super-gather. Only pairs of traces whose source-receiver separation does not exceed this value are correlated. This constrains the correlation to trace pairs with similar ray paths, reducing the effect of offset-dependent moveout on the shift estimates. Default: 100000 m (effectively unlimited). Set a smaller value to restrict correlations to near-offset trace pairs, which typically have higher signal-to-noise ratio. When multiple CO passes are used, this aperture is multiplied by CO Iteration Factor between passes.
The initial maximum CMP-to-CMP distance (in metres) used to select trace pairs for cross-correlation. Only pairs of traces from CMP bins within this distance of each other are correlated. Restricting this aperture limits cross-correlations to traces that share similar reflection geometry, improving the reliability of the estimated time-shifts. Default: 100000 m (effectively unlimited). When multiple CO passes are used, this aperture is also multiplied by CO Iteration Factor between passes.
The multiplicative factor applied to both the shot-receiver aperture (COSRAperture) and the CMP aperture (COCMPAperture) at the end of each coarsening pass. A factor greater than 1.0 progressively shrinks the apertures from pass to pass (when starting large), creating a multi-scale refinement strategy. A factor less than 1.0 would grow the apertures. Default: 1.5. Minimum: 1. This parameter has no effect when COIterCount is set to 1.
Selects which static components are included in the surface-consistent decomposition. This integer code controls whether the solver estimates shot statics only, receiver statics only, CMP statics, offset-dependent CMP statics, or combinations thereof. The default value activates the standard combined shot-and-receiver decomposition. Default: 2. Consult project documentation or support for the full list of mode codes if a non-standard decomposition is required.
The computed surface-consistent static correction values, stored as a static correction dataset containing per-source and per-receiver time shifts. These corrections can be connected downstream to a static application module to shift each trace by the appropriate source and receiver statics, improving the alignment of reflections across gathers and enhancing stack coherency.