The role of tectonics in geopressure compartmentalisation and hydrocarbon leakage in the deep offshore

The Niger Delta's deformation regime, controlled by NE-SW gravitational tectonics, forms imbricate thrust structures in the deep offshore, and generates profuse fluid expulsions expressed as pockmarks ±700 m and mud volcanoes ±2800 m in diameter. Gravity loading by sediment alone is not sufficient to explain the expulsions, and their classified morphology and proximity to the folds suggest a link with the structural compartmentalisation and pressure distributions. This work used 3D-seismic and well-data to link the leakages to active and inactive tectonic processes, highlighting the role of main and subsidiary faults and changing stress regimes before suggesting a "layer-by-layer" behaviour to explain the vertical and lateral geopressure compartmentalisation.