Paul Sava, Center for Wave Phenomena, Colorado School of Mines, Golden CO 80401, USA
Sergey Fomel, Bureau of Economic Geology, University of Texas (Austin), Austin, TX 78758, USA
A typical imaging condition for seismic reflection data
involves source and receiver wavefield matching, e.g. by
cross-correlation, at every image location.
This statement is true no matter how the two wavefields
are reconstructed, for example by
one-way wavefield extrapolation, or
two-way reverse-time extrapolation, or
Kirchhoff integral methods.
This statement is also true when the source and receiver
wavefields are reconstructed using different velocity models,
as is the case for imaging of converted waves.
Angle-dependent reflectivity information can be extracted
from the source and receiver wavefield by retaining multiple lags
of the imaging cross-correlation, i.e. by analyzing the match of
wavefields shifted relative to one-another.
Wavefields can be shifted in space (3D) or in time (1D), and
each shift method has an associated angle-decomposition method.
This paper explores the various types of imaging condition
using space- and time-shifts and
derives relations for angle decomposition for converted-wave
imaging.