Input data

Diffraction imaging requires as an input prestack unmigrated gathers and same RMS velocity field that is corresponding to the PSTM result that will be used for the reference.

Input seismic data

•Correct coordinates of source and receivers, including x, y, elevation, datum to be stored in trace headers

oFor that purpose a [Read seg-y traces] module should be used.

•All statics, including elevation component applied to the gathers.

oSince Geomage DI algorithm implemented from topography datum, the data must be shift to the surface datum prior execution.

oThe requirement to have data with elevation component applied is in order to allow the shift of the prestack gathers to actual surface datum with [Shift data] module. In case prestack gathers processed originally in g-Platform and can be used from the topography datum, there is no need to apply elevation statics component and this step can be skipped

•complete processing sequence applied to the gathers - the best pre-PSTM gathers

ono regularization must be applied, especially CMP-consistent (5DI or similar). Since reflection attenuation step have to be performed in common shot -> common receiver_line sorting, no cmp-consistent regularization allowed.

odata must not include any kinematic correction applied.

omute can be implemented in the data gathers, but from other side it's advised to have data unmuted to allow thorough testing of DI for shallower targets

Input RMS velocity

•RMS velocity field should be imported into g-Platform and similarly to prestack gathers should be on topography datum.

•DI application accept an RMS velocity model object as input. That velocity model should be created by [Create velocity model] module that allow import of different data types.

•This velocity field must corresponds to same processing that was applied in order to get best PSTM result. It is crucial to use the same velocity in order to get consistent results between the PSTM and DI attributes.