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3-D
Restoration Versus 3-D
Thickness Maps to Study the Evolution of Salt-Controlled Systems:
An Example from the Atwater Fold Belt, Gulf of Mexico
Oscar Fernandez1, Tim Buddin1, Norman Armstrong1, David MacConnell2, and Neil Gaynor2
1 Midland Valley Exploration, Glasgow, United Kingdom
2 BHP Billiton, Houston, TX
Restoration is frequently used as a tool to validate structural models and to study the evolution of structures in both 2D and 3D. Sequential restoration of 3D structural models makes it possible to infer and measure 3D growth patterns from the thickness of growth units. In salt controlled systems this approach is critical to define the timing of generation of traps, geometries adequate for migration, and welding of salt bodies.
True thickness (isopach) maps of unrestored 3D models can provide an equivalent measure of structural evolution as that derived from restoration, but with a smaller number of iterations. Furthermore, 3D thickness patterns can be used as a criterion for the validation of 3D structural models and to complete models in areas of poor seismic imaging.
A comparison between results of restoration and thickness map analysis is presented for an example from the Atwater fold belt. Despite decompaction and isostasy not being taken into account in the generation of the thickness maps, this technique provides sufficient information for a first-pass definition of temporal evolution and a validation of the geophysical interpretation.