2014-09-162014-09-161994-10-06CRUZ, João Carlos Ribeiro. Imageamento homeomórfico de refletores sísmicos. 1994. 142 f. Tese (Doutorado) - Universidade Federal do Pará, Centro de Geociências, Belém, 1994. Curso de Pós-Graduação em Geofísica.https://repositorio.ufpa.br/handle/2011/5734This thesis presents a new technique for seismic stacking called homeomorphic imaging, which is applicable to the imaging of seismic reflectors in a bidimensional, inhomogeneous and isotropic medium. This new technique is based on ray geometrical approximation and topological properties of reflection surfaces. For this purpose the concepts of wavefront, incidence angle, radius and caustic of wavefront and ray trajetory are used. Considering a circle as the geometrical approximation of the wavefront in propagation, it is possible to define diferent homeomorphic imaging methods, depending on processing configuration. In this way, the following methods are possible: 1) Common Source (Receiver) Element (CS(R)E), which relate to a set of seismograms with a single source (receiver) and a real reflected wavefront is considered; 2) Common-Reflecting-Element (CRE), which relate to a set of seismograms with a single reflection point and a wavefront hipotetically generated in the same reflection point is considered; 3) Common Evolute Element (CEE), which relate to a set of seismograms with each pair of source and geophone located in the same point on the seismic line and a wavefront hipothetically generated in the curvature center of the reflector is considered. In the first method is obtained a stacked seismic section using arbitrary central rays. In the last two methods the result is a zero-offset seismic section. These methods give also other two sections called radiusgram and anglegram, the latter being emergence angles and the former radii of wavefront in the moment that it reaches the observational surface. The seismic stacking is made using a local correction-time applied to the travel time of a ray that leaves the source, and after reflection, is registered as a primary reflection at a geophone, in relation to the reference time which is the travel time of the central ray. The formula used for the temporal correction depends on the radius, the emergence angle of the wavefront and the velocity which is considered constant near the seismic line. It is possible to show that in this new technique the registered signal is not submitted to stretch effects as a consequence of the temporal correction, furthermore there is no problem with reflector point dispersal as a consequence of dip reflectors, in contrast with the techniques that are based on NMO/DMO. In addition, considering that no a prori knowledge of a macromodel is necessary but the velocity near the seismic line, the homeomorphic imaging can be applied to inhomogeneous models without losing the strictness of the formulation.porAcesso AbertoProcessamento sísmicoImageamento sísmicoInversão - GeofísicaMétodo de reflexão sísmicaTeoria do raioTeseCNPQ::CIENCIAS EXATAS E DA TERRA::GEOCIENCIAS::GEOFISICA::GEOFISICA APLICADA