paul@sep.stanford.edu

Paul Sava* Stanford University

Sergey Fomel UT Austin (UC Berkeley)

Angle-domain common-image gathers

paul@sep.stanford.edu

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

paul@sep.stanford.edu

Agenda

Common-image gathers

ADCIG methodology

Definitions

Offset vs. angle

Computational space

Examples

paul@sep.stanford.edu

Offset-Domain Common Image Gathers

Kirchhoff Wave-equation

z

h

z

hflat events focused events

paul@sep.stanford.edu

Angle-Domain Common Image Gathers

Kirchhoff Wave-equation

z

z

flat events flat events

paul@sep.stanford.edu

Example

paul@sep.stanford.edu

Agenda

Common-image gathers

ADCIG methodology

Definitions

Offset vs. angle

Computational space

Examples

paul@sep.stanford.edu

Reflection schemeSource Receiver

V(x,y,z)

2h

v

paul@sep.stanford.edu

Wave-equation ADCIG methods

Reflection angle () Offset ray-parameter (ph)

z

h

k

ktan

h

h

kp k-domain

(RTT)

h

z

tanh

tph

x-domain

(slant-stack)

IMAGE space DATA space

paul@sep.stanford.edu

Agenda

Common-image gathers

ADCIG methodology

Definitions

Offset vs. angle

Computational space

Examples

paul@sep.stanford.edu

Wave-equation CIGs: example

ODCIG ADCIG

paul@sep.stanford.edu

ADCIG: vs. ph

paul@sep.stanford.edu

Summary

• CIG domains– offset or angle

• CIG concepts– flatness: Kirchhoff– focusing: wave-equation

• Wave-equation ADCIG– data space– image space