Migração pré-empilhamento Kirchhoff feixes gaussianos 2,5D nos domínios afastamento comum e ângulo-comum

Abstract

A Kirchhoff-type migration is considered in the geophysics literature as one of the most fundamental tools in seismic data processing, the base for solution of several imaging problems. In this respect, it must be considered its wide use and its successful history for the oil and gas industry, associated with its low computational cost and flexibility to deal with non-wavefield datasets when compared to other methods. However in 3D, even when compared to other existing and most effective methods, its computational cost and implementation is still considered high, due to several reasons: new acquisition technologies, data storage and burden, azimuth richness, etc. Thus the main objective of the present work is to implement and simulate migration results (i.e., images) with high signal-to-noise ratios and with a less computer burdens in 2.5D media, using the theoretical framework of Gaussian Beams (GBs). By considering one implementation of a superposition of GBs integral operator studied by Ferreira and Cruz (2009) and by the use of the stationary phase method (Bleistein, 2000), a new integral superposition migration operator using paraxial fields (i.e., GBs) was implemented and studied. Theoretically speaking, the present migration operator was inserted in the kernel of a conventional, 2.5D, true-amplitude, prestack Kirchhoff migration integral operator, thus defining a 2.5D prestack Kirchhoff-Gaussian Beam (KGB) migration operator. The present migration operator was later configured to hold commonoffset (CO) and common-angle (CA) seismic acquisition configurations. I remark that in the present thesis one flexibility of the GB migration operator was idealized in order to handle its effective application in more the one sorting configuration, i.e., common-offset and commonsource.