MF Interpolator Distributed

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MF Interpolator Distributed

 

Description

The MF Interpolator Distributed module creates a Multi-Focusing (MF) seismic image and optionally an MF velocity field by interpolating pre-computed MF search results from a KDB database file. For each output bin, the module gathers MF wave collection results from a neighbourhood of nearby bins in the database, applies a time-shift correction to align the data to the output bin position, and stacks the contributions to form the final image trace. The distributed version of this module supports parallel execution across multiple cluster nodes, with each node processing a sub-range of inlines or crosslines.

Use this module after a Multi-Focusing search (ZO-MF or CO-MF) has been completed and the results stored in a KDB file. The module converts those search results into a regular SEG-Y stack image and/or a velocity field that can be used for subsequent interpretation or further processing. For large 3D surveys, run this module in distributed mode to speed up image creation by splitting the work across cluster nodes.

Input data

Output file name

Path to the output GSD file where the computed MF image (stack and/or velocity field) will be written. Specify a full file path with the .gsd extension. In distributed mode each node writes results to this file in the mode specified by Write mode.

Using storage type

Selects whether to read MF results from a 2D or 3D KDB database file. Set to 2D when the input database was produced by a 2D MF search, or to 3D for a 3D MF search database. Default: 2D.

Storage file 2D

Path to the 2D MF KDB database file containing the pre-computed Multi-Focusing search results. Connect this input when Using storage type is set to 2D.

Storage file 3D

Path to the 3D MF KDB database file containing the pre-computed Multi-Focusing search results. Connect this input when Using storage type is set to 3D.

G3DPickingItem

Optional link to an MF picking item containing user-defined picks that can be used to guide the interpolation or restrict stacking to specific time-space windows.

File with polygons

Optional path to a polygon file defining spatial masks. Bins outside the polygon boundaries will be excluded from the image creation.

V0 Map

Optional link to a spatially varying V0 (near-surface velocity) map used to apply datum and elevation statics corrections to the MF image traces.

Parameters

Create NMO corrected gathers

When enabled, outputs NMO-corrected common image gathers in addition to the stacked image. Default: disabled. Enable this option when you need to inspect the gather flatness for velocity QC after MF imaging.

Find Central Bin

When enabled, the module searches for the nearest calculated MF bin in the database for each output bin and centres the interpolation aperture on that bin. Default: enabled. Keep this enabled for best image quality; disable only in special cases where the output grid exactly matches the MF search grid.

Image creation parameters

Container group linking to the common image creation parameter set shared with the MF search engine. These parameters define the sample rate, record length, and amplitude scaling applied to the output image traces.

Mute type

Selects how the stacking aperture mute is applied. Options are Use mute function (applies a user-defined time-offset mute curve from the database) and Use mute factor (applies a simple stretch-based mute using the MuteFactor threshold). Default: Use mute factor.

MuteFactor

Mute threshold applied when Mute type is set to Use mute factor. Default: 1000. Traces or time samples where the MF shift exceeds this factor are zeroed out. Reduce this value to mute more aggressively in zones of poor signal quality.

Interpolation Window Length

Length (s) of the time window used to interpolate MF shift values between the surrounding bins when aligning data to the output bin position. Default: 0.010 s (10 ms). A longer window averages more of the shift function and produces smoother shifts; a shorter window preserves more of the spatial detail in the wavefield.

Stabilisation Window Length

Length (s) of the time window over which the shift function is smoothed to reduce high-frequency noise in the MF correction operator. Default: 0.010 s (10 ms). Increase this value to suppress high-frequency jitter in the shift field at the cost of temporal resolution of the correction.

Write mode

Controls how output traces are written to the output GSD file. Direct overwrites any existing file content. Append adds new traces to an existing file, which is required when merging results from multiple distributed nodes into a single output file. Default: Direct.

From inline

First inline number of the sub-region of the survey to be processed by this node. Set to -1 to process from the start of the survey. In distributed mode, each node is assigned a different inline range to process in parallel. Default: -1.

Till inline

Last inline number of the sub-region to be processed by this node. Set to -1 to process to the end of the survey. Default: -1.

From crossline

First crossline number of the sub-region to be processed. Set to -1 to process from the crossline minimum. Default: -1.

Till crossline

Last crossline number of the sub-region to be processed. Set to -1 to process to the crossline maximum. Default: -1.

Output geometry

Container group specifying how the output image geometry is defined.

Using output geometry type

Selects the source of the output grid geometry. Options are: Use storage geometry (use the bin grid embedded in the KDB database), Bin vector, Bin grid (use a connected BinGrid item), and Trace vector (use a connected trace header vector). Default: Use storage geometry.

Output bin grid

Link to a BinGrid item defining the output image grid, used when Using output geometry type is set to Bin grid.

Trace headers

Link to a trace header vector defining the output image positions, used when Using output geometry type is set to Trace vector.

Output bin vector

Link to a bin point vector defining the output image positions, used when Using output geometry type is set to Bin vector.

Apertures

Container group controlling the spatial aperture used to gather MF results from surrounding bins.

Max Distance To MF CMP

Maximum distance (m) from the output bin to a MF database bin for that bin to be included in the interpolation. Default: 50 m. Increase this value when the output grid is coarser than the MF search grid to ensure enough contributing database bins are found at each output location.

Maximum number of used MF Bins

Maximum number of database bins that contribute to the stack at each output bin location. Default: 8. Increasing this value improves the redundancy of the stack but increases computation time. A value of 1 is equivalent to nearest-neighbour selection.

Testing

Container group with advanced options controlling how MF time shifts are applied to each trace.

Shift Type

Method used to apply the MF time-shift correction to each trace. Options: Shift use windows (applies the shift within overlapping time windows), Shift use stretching (applies the shift as a time-stretch correction), Shift use windows only on extremes (applies windowed shifts only at the ends of the trace). Default: Shift use windows.

Types

Container group selecting which output products are computed.

Stack

When enabled, the module outputs a MF stacked image volume. Default: enabled. This is the primary output used for interpretation.

Velocity

When enabled, the module also outputs a velocity field derived from the MF search results. Default: disabled. Enable this to extract a kinematic velocity model from the Multi-Focusing analysis for use in depth conversion or interval velocity estimation.