Selective stacking in the reflection-angle and azimuth domain

Yaxun Tang

tang@sep.stanford.edu

ABSTRACT

I analytically demonstrate the existence of artifacts in angle-domain common-image gathers (ADCIGs) caused by sparsely sampled wavefields from the perspective of shot-profile migration. The subsurface-offset domain common-image gather (SODCIG) is linearly related to the ADCIG in locally constant-velocity media when the wavefields are sufficiently well sampled, but not when the wavefields are poorly sampled. Hence, linear slant-stack or radial-trace transform in SODCIGs will produce ADCIGs with artifacts, which might hinder further interpretation or analysis and reduce the quality of the final stacking image. Instead of simply stacking along reflection angle and azimuth axes, I present a method to compute the stacking weights as functions of angle and azimuth and make the stacking process selective. My method is tested on the synthetic wide-azimuth version of the SEG/EAGE salt data set, where a cleaner image with higher signal-to-noise ratio is obtained.