Resumo

TORRES-VEGA, Claudia Milena; ALMANZA-MONTERO, Ovidio Amado  e  MONTES-VIDES, Luis Alfredo. METHODOLOGY TO REDUCE FAULT SHADOW: APPLIED IN A SECTOR OF THE LLANOS BASIN - COLOMBIA. bol.geol. [online]. 2017, vol.39, n.2, pp.57-66. ISSN 0120-0283.  https://doi.org/10.18273/revbol.v39n2-2017004.

The shadow fault distorts the image of the hanging block of normal and inverse faults, caused by strong lateral velocity changes that deviates the ray path of waves. In the Llanos basin, this effect creates in the seismic images false structures like anticlines (pull up) and synclines (push down or sag). In this paper, the factors that generate this effect and its impact on the seismic images are studied through numerical modeling. It is defined a methodology to identify the fault shadow and its causing factors, and to create the appropriate model for the pre stack depth migration - PSDM. The methodology was tested with synthetic seismograms and applied to a seismic line recorded in a sector of the Departamento de Casanare-Colombia. As a result, a reliable image in depth free of fault shadow was obtained. Even the methodology was used in a sector with normal fault it is applicable to zones with inverse faults.

Palavras-chave : fault shadow; false structure; numeric modeling; llanos basin; Casanare.

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