3D geomechanical restoration of restraining bend systems in the outer fold-and-thrust belt of the deep-water Niger Delta using fault-slip constraints.

Pauline Durand-Riard and John H. Shaw and Andreas Plesch. ( 2011 )
in: Proc. 31st Gocad Meeting, Nancy

Abstract

In the outer fold-and-thrust belt of the deep-water Niger Delta basin, deformation is largely focused on thrust-fault systems. In some locations, particularly in the northern part of the Delta toe, gradients in the shortening are also accommodated by the development of transport-parallel tear faults. The high quality of the 3D seismic data in the region allows us to accurately describe the architecture of the tear fault systems and their relationships with the thrust faults. This analysis has identified several steps or relays between tear fault splays, within which the tear fault dip generally increases with depth resulting in restraining and releasing bend architectures. While the kinematics and mechanics of the thrust systems have been largely documented, the deformation occurring within the restraining bends is poorly known. We investigate deformation along these tear fault systems by (i) mapping in detail one particular restraining bend system in order to understand the 3D relationships between the different types of faults, and (ii) generating a synthetic balancing model of a restraining bend system and sequentially restoring it in 3D. Classical boundary conditions are combined with fault slip conditions to better constrain the strike slip and compared to restoration results using constrained displacement. Restoring such a simplified model is a first step towards an improved assessment of the deformation required to accommodate the tear-faults displacement within the restraining bends. Using fault-slip constraints provides a new realistic approach for using geologic observations to constrain 3D restorations, enhancing the effectiveness of these methods in addressing deformations associated with strike- and oblique slip fault systems.

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BibTeX Reference

@inproceedings{Durand-RiardGM2011,
 abstract = { In the outer fold-and-thrust belt of the deep-water Niger Delta basin, deformation is largely focused on thrust-fault systems. In some locations, particularly in the northern part of the Delta toe, gradients in the shortening are also accommodated by the development of transport-parallel tear faults.
The high quality of the 3D seismic data in the region allows us to accurately describe the architecture of the tear fault systems and their relationships with the thrust faults. This analysis has identified several steps or relays between tear fault splays, within which the tear fault dip generally increases with depth resulting in restraining and releasing bend architectures. While the kinematics and mechanics of the thrust systems have been largely documented, the deformation occurring within the restraining bends is poorly known.
We investigate deformation along these tear fault systems by (i) mapping in detail one particular restraining bend system in order to understand the 3D relationships between the different types of faults, and (ii) generating a synthetic balancing model of a restraining bend system and sequentially restoring it in 3D. Classical boundary conditions are combined with fault slip conditions to better constrain the strike slip and compared to restoration results using constrained displacement.
Restoring such a simplified model is a first step towards an improved assessment of the deformation required to accommodate the tear-faults displacement within the restraining bends.
Using fault-slip constraints provides a new realistic approach for using geologic observations to constrain 3D restorations, enhancing the effectiveness of these methods in addressing deformations associated with strike- and oblique slip fault systems. },
 author = { Durand-Riard, Pauline AND Shaw, John H. AND Plesch, Andreas },
 booktitle = { Proc. 31st Gocad Meeting, Nancy },
 title = { 3D geomechanical restoration of restraining bend systems in the outer fold-and-thrust belt of the deep-water Niger Delta using fault-slip constraints. },
 year = { 2011 }
}