--> Abstract: Exploring Complex Thrust Structures with 3D Seismic in the Eastern Venezuelan Serrania, by J. F. Flinch, R. Martinez, J. A. Martinez, S. Mata, and C. Sanchez; #90942 (1997).

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Abstract: Exploring complex thrust structures with 3D seismic in the Eastern Venezuelan Serrania

FLINCH, J. F., R. MARTINEZ, J. A. MARTINEZ, S. MATA and C. SANCHEZ

The Eastern Venezuelan Serrania is one of the fold-and-thrust belts with more 3D seismic surveys available. The quality of the data and the complexity of the structure requires the use of alternative techniques and expertise different from 3D interpretation of passive-margins or non-deformed regions. The use of time slices is a key tool to map these complex structures. Zap programs should be used very careful because of the poor continuity of reflectors. Several examples were chosen to illustrate the advantage of 3D versus 2D seismic and the new concepts on thrust tectonics. Apparently simple fault-bend-folds or ramp anticlines become forethrusts with hangingwall backthrust duplexes, backthrusts with hangingwall forethrust duplexes or "Fish-Tail"(zig-zag) double-vergent thrust systems. Mapping includes stratigraphic levels in the hangingwall and footwall as well as detachment levels. 3D seismic interpretations permit to construct hangingwall and footwall cut off and branch lines map. These maps are used to restore 3D thrust displacement and calculate thrust transport direction.

The new interpretations have important implications for exploration and production of already discovered fields. In the northern Monagas area of the Venezuelan Serrania (Furrial-Boqueron-Orocual-Quiriquire Trend) where giant oil fields already exist, these techniques are used to re-evaluate reserves and propose new prospects.

AAPG Search and Discovery Article #90942©1997 AAPG International Conference and Exhibition, Vienna, Austria