Chevron U.s.a. Inc.

Harry L Martin

E Frederic Herkenhoff

Richard B Alford

E Fredrick Herkenhoff

Jonathan D Cocker

Frederic E Herkenhoff

The present invention provides a method and apparatus for arriving at true relative amplitude destretched seismic traces from stretched seismic traces. The method compensates for offset varying reflection interference effects due to normal moveout. Stretch factors &#x3b2; and also input spectra are determined for NMOR stretched seismic traces. Estimates are then made of stretched wavelet spectra from the input spectra. A destretched wavelet spectra is then obtained. Shaping correction factors are determined by taking the ratio of the destretched wavelet spectra to the stretched wavelet spectra and are applied to the input spectra of the stretched traces to arrive at a destretched trace spectra. True relative amplitude scaling factors are computed by taking the ratio of a true relative amplitude property of the destretched wavelet spectra to a corresponding true relative amplitude property of the stretched wavelet spectra. Finally, the true relative amplitude scaling factors are applied to the destretched trace spectra to arrive at true relative amplitude destretched seismic traces.

Method and apparatus for true relative amplitude correction of seismic data for normal moveout stretch effects

A method for processing seismic traces to provide enhanced signal-to-noise ratio in seismic data is provided. A seismic survey of traces is obtained which has been collected over an areal region containing a grid of nodes. A rolling supergather aperture is used to select a subregion containing a working subset of traces. A model subset of traces is selected from proximate the center of the working subregion. The model subset of traces are composited to form a model trace. A modified subset of traces is created by comparing the individual traces with the model trace using an alignment technique, which is preferably a time varying trim statics technique. These modified subsets of traces may then be composited into a reduced set of enhanced seismic traces having enhanced signal-to-noise ratio relative to the original seismic traces. The rolling supergather aperture is then incrementally moved until traces from all over the areal region are chosen and enhanced subsets of seismic traces have been assembled into a set of seismic data having enhanced signal-to-noise ratio.

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San Ramon, CA, United States of America

Harry L Martin