Abstract: A method for moveout-correcting CDP gathers of seismic data that takes nonhyperbolic moveout at large offsets into account. The entire range of offsets is divided into smaller ranges. Within each smaller range, a curve is fitted to the reflection time vs. offset data, and these separate curves are made to be continuous at range boundaries. The curves may be the hyperbolic or quartic options available in commercial seismic data processing packages. Additional computation time required due to lack of a single velocity function can be compensated for by interpolation techniques. The method has application to, inter alia, AVO analysis.

Abstract: A method for deriving reservoir lithology and fluid content for a target location from pre-stack seismic reflection data. The method uses inversion of pre-stack seismic reflection data for both the target location and a calibration location having known subsurface lithology and fluid content to derive the subsurface lithology and fluid content at the target location. The inversion process is preferably a viscoelastic inversion to account for the effects of friction on seismic wave propagation. The results of the inversion process are a set of subsurface elastic parameters for both the target and calibration locations. Relative magnitudes of these subsurface elastic parameters are compared, together with the known subsurface lithology and fluid content at the calibration location, to derive the subsurface lithology and fluid content at the target location.