| The offshore Nile Delta is characterized by variations of the maximum horizontal stress orientation in subsalt and supra-salt sequences. Margin-parallel SH, typical for tertiary deltas, is observed for regions that are below or do not contain evaporites. In sequences underlain by evaporates pre-dominantly margin-normal SH is observed. This observation yielded the first conclusive in situ evidence that salt acts as a mechanical detachment layer. In this study, 3D finite element analysis (FEA) is used to simulate the total stress distribution in the offshore Nile Delta featuring evaporate sequences. Several parameters such as different salt sequence geometries, friction coefficient on faults, and salt viscosity are considered. The numerical modeling results are used to evaluate if possible basal drag forces or mechanical property contrast effect induced by gravitational gliding result in varying stress orientations and if the observed stress orientations in the Nile Delta can be explained and correlated by the numerical modeling results. Implication of the modeling results for hydrocarbon production will be analyzed and discussed. |
