O uso de atributos para o realce de eventos de difração em imagens de GPR no domínio do OFFSET comum

Abstract

For the geophysical investigation methods seismic and GPR, which are based on propagation of waves in the middle and the recording of the return of these waves to the receiver on the surface, we can highlight 3 possibilities of recorded events: reflections, refractions and diffractions. Like reflection, diffraction is a phenomenon that occurs with wave fronts, both electromagnetic and acoustic. The diffraction occurs with wave fronts that reach edges, vertices or corners of boundary surfaces; discontinuities; objects, particles or obstacles that act as points. Local structures and lithology are features that cause diffraction. They can be fractures, faults, geological bodies like intrusions and bioherms and reefs, salt domes and discontinuities of layers of rock. However, diffractions are commonly considered noise. This work presents a pioneering methodology for the enhancement of diffraction: the use of GPR attributes that measure the kinematic and energy properties related to diffractions, distinguishing them from the reflections events. The methodology consists of estimate the dip, the curvature and amplitude of the diffractions that differentiate them from the reflections and use such a distinction to eliminate the latter. This results in an image with enhanced diffractions.