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The Tie Stacks module calculates the time mis-tie (static shift) between a modeled stack and an observed stack by cross-correlating the two. It determines the per-trace time shift required to align the observed stack with the model, then optionally applies those shifts back to either the stacked data or the original pre-stack seismic traces. This is particularly useful in well-tie workflows where a synthetic seismogram is used as the model and the real stack needs to be adjusted to achieve a consistent tie across the survey.
The module runs in two stages. First, execute the module with the two stack inputs connected to compute the mis-tie shifts. The corrected output stack is produced immediately in the Output stack data stream. Second, use the Apply custom action to apply the calculated shifts to a separate SEG-Y file of pre-stack data; this step reads the input file, applies the shifts trace-by-trace (split between source and receiver corrections if SR mode is selected), and writes the result to the output file.
The reference (model) stack to which the observed stack will be aligned. This is typically a synthetic seismogram or a prior-processed stack representing the desired alignment target. The model stack must have the same number of traces, sample interval, and record length as the observed stack.
The observed (real) stack that will be correlated against the model stack. The module computes per-trace time shifts to align this data to the model.
The time length of the Automatic Gain Control window applied to both the model and observed stacks before cross-correlation, in seconds. AGC normalises the amplitude envelope of both datasets so that the correlation is driven by waveform shape rather than amplitude differences. Smaller windows (e.g. 0.2 s) give tighter amplitude normalisation; larger windows (e.g. 1 s) apply a gentler gain adjustment.
Default: 0.5 s.
When enabled, a Gaussian taper is applied at the overlap zones of the AGC window, producing a smoother gain function and reducing edge artefacts. Enable this option when the data has strong amplitude contrasts at the window boundaries.
Default: enabled.
When enabled, the AGC gain function is computed across all traces simultaneously (using the combined energy of all channels) rather than independently per trace. This produces a more consistent relative amplitude between traces after gain application. Enable when you want to preserve lateral amplitude variations after AGC.
Default: disabled.
The start time of the cross-correlation analysis window, in seconds. Only the portion of each trace between Time start and Time end is used for correlation. Set this to the top of the interval of interest — typically the shallowest horizon where the tie is needed. Set to -0.001 to use the top of the trace.
Default: -0.001 s (full trace).
The end time of the cross-correlation analysis window, in seconds. Set this to the base of the target interval. Using a focused window around the zone of interest typically gives more reliable mis-tie estimates than using the full trace.
Default: -0.001 s (full trace).
The number of neighbouring traces mixed together before cross-correlation. Trace mixing improves the signal-to-noise ratio of the correlation estimate and reduces the sensitivity to individual noisy traces. Increasing this value smooths the resulting mis-tie curve spatially but reduces spatial resolution. A value of 1 applies no mixing.
Default: 5 traces.
The maximum allowable time shift in seconds that the cross-correlation is permitted to detect. The search for the correlation peak is restricted to lags within ±MaxShift. Set this to a value slightly larger than the largest mis-tie you expect; a value of 0 disables the limit and allows the full correlation lag range.
Default: 0 s (unlimited).
Controls how the calculated mis-tie shifts are applied when the Apply custom action is triggered on the pre-stack input file:
CMP — each pre-stack trace is shifted by the mis-tie value of the nearest CMP bin. All traces in the same bin receive the same correction.
SR — the mis-tie correction is split equally between the source and receiver positions. Each trace receives half of the source-side correction and half of the receiver-side correction, derived from the nearest source and receiver bin locations respectively. Use this mode when you intend to apply the correction to pre-stack gathers that will be subsequently restacked.
Default: CMP.
The full path and file name of the SEG-Y seismic file (.sgy or .segy) to which the mis-tie corrections will be applied when the Apply custom action is triggered. This is typically the pre-stack or stacked SEG-Y file that you want to shift. Only used during the Apply action; not required for the initial mis-tie calculation.
The full path and file name of the output SEG-Y file where the shift-corrected traces will be written. The file will contain the same traces as the input file but with the mis-tie time shifts applied according to the selected Calculation Type. Only used during the Apply action.
The time-shifted corrected stack, produced after the main execution. Each trace of the observed input stack has been shifted by the mis-tie value computed from cross-correlation with the corresponding model stack trace, aligning the output with the model.