2D CO map migration

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2D CO map migration

 

Description

Function for transformation of V RMS-COMFinto map migrated velocity

 

The procedure of map migration is a spatial transition(migration) of the velocity field to the accurate position that is connected with the normal ray. For this purpose, the velocity is displaced from the stack domain to the migration domain for subsequent migration. This performed according to optimal values of radius of curvature RCRE and emergency angle Beta for the imaging point at each time sample. Unlike ZOMF(map migration), COMF map migration calculated for each offset class and final velocity is the sum of all velocities of offset classes.

 

Input data – CO-MF database data handle.

Output data – Map migrated velocity filled/unfilled.

Visual – VMF-RMS, Map migrated velocity, Map migrated velocity filled, semblance

 

Input data

Storage file

 Link to storage file containing calculated database of CO-MF

GMFPickingItem

 Link to velocity constrain picking that can be taken from another procedure

Parameters

Max aperture for migration

 Migration aperture that will be used for map migration of the velocity field

Image creation parameters

 Group of settings controlling how output velocity image panels are constructed after the map migration run. Governs the spatial grid, time range, and display scaling for VMF-RMS, Map migrated velocity, Map migrated velocity filled, and semblance panels.

Use all offsets

 Will use all offset classes for map migration

Create images before run

 When enabled, generates the visual output panels before the main migration processing begins, allowing inspection of the input velocity field and semblance quality prior to the full run. Useful for parameter tuning on large datasets.

Threshold semblance

 Minimum semblance value required for a velocity sample to be accepted in the migrated output. Samples below this threshold are excluded. Higher values produce sparser but more reliable results. Typical range: 0.1 to 0.5.

Vrms mig type

 Type of optimal velocity selection. During the migration can occur situation when few velocities migrated into the same sample. The final velocity can be chosen or by                maximum correlation, or can be calculated an average of all velocities migrated into this sample.

Stack mig type

 Controls how velocities from different offset classes are combined when multiple contributions map to the same output sample: Summation (standard CO-MF formulation) or Weighted average (preferable when offset classes have uneven quality).