Processing for stratigraphic objectives

Abstract

Stratigraphic objectives require careful attention beginning with acquisition and continuing throughout the processing sequence. This paper reviews some of the fundamental aspects of processing that ensure the data for stratigraphic interpretation and modeling is the best possible representation of the subsurface. To be successfully inverted and accurately interpreted, the data must be as free of noise and multiples as possible, contain as broad a range of frequencies as possible, and reflect true amplitude relationships. Appropriate geophone array and geophone interval values make certain that the higher frequencies are recorded unambiguously. Complete and correct system signature, and predictive deconvolution ensure that the data stacks in phase and closely resembles the earth. Velocity spectra must adequately sample the lithologic and structural variations along the line and be interpreted before and after statics corrections for the best resolution. Furthermore, statics and amplitude adjustments must be surface-consistent so that time and amplitude variations truly represent the subsurface. Wave equation migration maintains the amplitude and frequency relationships in the data while correcting the spatial relationships of dipping and faulted reflectors. When these considerations are properly addressed, stratigraphic interpretation and related studies such as trace inversion and modeling will add meaningful information to the explorationists' picture of the earth's lithology.