Paul Sava* Stanford University Sergey Fomel UT Austin (UC Berkeley) Angle-domain common-image gathers

Common Image Gathers Representations of the seismic events sorted by their location in the subsurface Image domain –offset-domain –angle-domain Classes of methods –Kirchhoff –Wave-equation S-G migration shot-profile migration

Agenda Common-image gathers ADCIG methodology Definitions Offset vs. angle Computational space Examples

Offset-Domain Common Image Gathers KirchhoffWave-equation z h z h flat eventsfocused events

Angle-Domain Common Image Gathers KirchhoffWave-equation z  z  flat events

Example

Agenda Common-image gathers ADCIG methodology Definitions Offset vs. angle Computational space Examples

Reflection scheme SourceReceiver V(x,y,z)     2h v 

Wave-equation ADCIG methods Reflection angle (  ) Offset ray-parameter (p h ) k-domain (RTT) x-domain (slant-stack) IMAGE spaceDATA space

Agenda Common-image gathers ADCIG methodology Definitions Offset vs. angle Computational space Examples

Wave-equation CIGs: example ODCIGADCIG

ADCIG:  vs. p h

Summary CIG domains –offset or angle CIG concepts –flatness: Kirchhoff –focusing: wave-equation Wave-equation ADCIG –data space –image space