Amplitude-preserving wave-equation migration Paul Sava* Stanford University Biondo Biondi Stanford University
The problem Recover reliable migration amplitudes: i.e. reflectivity as a function of incidence angle Reflectivity description Describe reflectivity as a function of incidence angle Migration algorithm Apply amplitude corrections to the migration operator Illumination balance Restore amplitudes in shadow zones
Agenda Amplitude corrections Angle-domain common image gathers Imaging effects Propagation effects Acquisition effects Definitions Methods Applications
Common image gathers z h flat events z h focused events z flat events z Wave-equationKirchhoff Offset domain Angle domain
Angle-Domain Common Image Gathers SourceReceiver V(x,y,z) 2h v S-G migration Prucha et al., 1999 Sava et al., 2001 Shot-profile migration de Bruin et al., 1990 Rickett & Sava, 2001
ADCIG: S-G migration
Agenda Amplitude corrections Angle-domain common image gathers Imaging effects Propagation effects Acquisition effects Definitions Methods Applications
Modeling operator modeling migration
Jacobian weighting: arbitrary geometry 2h s image space data space
Jacobian weighting: flat reflectors (Wapenaar et al., 1999) 2h s image space data space
Jacobian weighting Ideal offset-gather Ideal angle-gather Reflection angle Offset ray parameter
Jacobian weighting Ideal offset-gather Ideal angle-gather Reflection angle Offset ray parameter
Agenda Amplitude corrections Angle-domain common image gathers Imaging effects Propagation effects Acquisition effects Definitions Methods Applications
WKBJ & scattering operators Clayton & Stolt (1981) Stolt & Benson (1986)
Agenda Amplitude corrections Angle-domain common image gathers Imaging effects Propagation effects Acquisition effects Definitions Methods Applications
Stationary-phase operator 2-D CAM Bleistein & Handelsman (1975)
Agenda Amplitude corrections Angle-domain common image gathers Imaging effects Propagation effects Acquisition effects Definitions Methods Applications
Applications Pseudo-unitary migrationTrue-amplitude migration
Example: vertical section
Example: vertical section
Example: horizontal section uncorrected
Example: horizontal section corrected
Summary Amplitude-preserving transformation to the angle domain Amplitude corrections –imaging effects –propagation effects –acquisition effects