Application of Nonstretch NMO in Seismic Reflection Data Processing

We describe the implementation of nonstretch normal-moveout (NMO) correction which decreases the stretching effects of conventional NMO correction. Unlike conventional NMO, the method implies that the velocity decreases with time for a finite time interval of a seismic pulse. In this method, stretching can be avoided by keeping the parallelism of NMO traveltimes as much as possible. This method has been tested on synthetic and real seismic reflection data. The advantages of nonstretch NMO include preservation of higher frequencies and reduction of spectral distortions at far offsets. In this method, a significant range of large offsets that normally would be muted in the case of conventional NMO can be kept and used, thereby leading to better stack. Nonstretch NMO could be advantageous for amplitude-variation-with-offset purposes.