Crs Processing Technique

Sunjay S. Sunjay
GEOPHYSICS, BHU, Varanasi, India

The Common Reflection Surface (CRS) method is a macro-model independent imaging method in time domain. Unlike the conventional NMO/DMO stacking surfaces, the CRS stacking surfaces extend beyond single common-midpoint (CMP) gathers. This implies a much higher fold, which leads to a better signal-to-noise ratio, and reflector continuity in the CRS stack. Moreover, dipping layers are strongly enhanced, since dip is explicity included in the CRS subsurface model.

The CRS stack is a technique to derive an optimum Zero Offset Stack. This is done by calculating the stacking operator that approximates the reflections in a multicoverage dataset best.The CRS technique can be an alternative in areas where prestack depth migration fails to enhance the subsurface resolution. Poststack depth migration can be applied to transform the CRS stack into a high resolution depth section. As a further advantage, this depth processing scheme is less costly than prestack depth processing.The AVO improvements by CRS are based on CRS supergathers, and on the CRS moveout correction. The moveout correction aligns reflection of any dip across the whole supergather, and the large portion of data in the supergather provides a stabilized AVO result.

Presentation GEO India Expo XXI, Noida, New Delhi, India 2008©AAPG Search and Discovery