--> A Dynamic Approach to Understanding the Structural and Stratigraphic Evolution of the Niger Delta, by Michael G. Mann, Rich Wiener, Valerie Goggin, and David Advocate; #90037 (2005)

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A Dynamic Approach to Understanding the Structural and Stratigraphic Evolution of the Niger Delta

Michael G. Mann1, Rich Wiener2, Valerie Goggin2, and David Advocate2
1 ExxonMobilExploration, Houston, TX
2 ExxonMobilExploration

A key hypothesis in the Niger Delta is that the stratigraphic succession and reservoir, seal and source distribution is controlled by the paleostructural evolution of the delta. Basement architecture in the oceanic crust, related mostly to transform faults, had a strong influence on the early sedimentation in the delta. The Niger delta began developing in Eocene time, and by Oligo-Miocene time updip detached extension was driving down dip contraction in a linked structural system; tear faults form part of the linkage where differential movement in the delta occurs. While the early, detached structures are not basement involved, the preexisting basement features had a strong influence on where subsequent structures and related sub-basins formed. Key examples are the Charcot fracture zone, which splits the delta into two distinct lobes and the Fernando Po fracture zone, which controls the position of the eastern foldbelt. The linked extension and contraction set up an evolving paleotopography in the basin. This evolving structural deformation (mainly folds and thrusts) was the controlling factor in the stratigraphic succession in the delta, influencing the evolution of the toe of slope, basin floor, slope channels and shelf margin depositional systems. This paleotopography also influenced source deposition. Knowledge of the timing and distribution of these structurally influenced stratigraphic systems provides important insights into the paleogeography of the basin and into understanding play elements across the delta.