Modelling
Tectono-Sedimentary Processes in Atlantic Margin Salt Basins: Understanding the
Evolution of the Deepwater Slope and Allochthonous Salt Sheets
Adam, Juergen1, Csaba Krezsek1,
Cody MacDonald1, Clarke Campbell1, Djordje Grujic1
(1)
Atlantic margin basins exhibit extensive
thin-skinned extension over salt. The tectono-stratigraphic evolution of the
shelf, slope and deepwater areas are gravity-driven, which causes feedbacks
between sedimentation, faulting and salt mobilisation. Petroleum exploration in
the these dynamic depositional environments, especially in the deepwater with
limited well control and poor seismic imaging due to complex salt diapirs,
canopies and sheets remains challenging. 4D physical modelling with optical
deformation monitoring and 2D/3D seismic interpretation simulates passive
margin salt basin evolution and allows the quantitative assessment the role of
sedimentation and pre-salt basement topography on the timing and mechanisms of
faulting, sedimentation and salt mobilization from the shelf to the deepwater
extension. Our results show that basin evolution is strongly controlled by
pre-salt basement topography and sedimentation. The experiments reproduce
complex salt basin structures including growth fault/roller structures,
reactive and active diapirs, turtle structures, canopies, and allochthonous
salt nappes. The results show that the evolution of the shelf and slope
depo-centers are characterized by highly variable and localized subsidence patterns
and are linked spatially and temporally with deepwater toe fold-belts, inflated
salt complexes and allochthoneous salt sheets. New mechanical concepts and
interpretation templates derived from integrated 4D physical simulations with
2D/3D structural and seismic tools will lead to a new generation of improved
interpretation templates for salt-related structures and depositional systems
in Atlantic margin basins. Knowledge gained from the study will be especially
relevant for exploration in the slope and deepwater domains.
AAPG Search and Discover Article #90063©2007 AAPG Annual Convention, Long Beach, California