Evidence for low-angle, subhorizontal hanging faults in rotated fault blocks, Cabinda, offshore Angola

Abstract

Extensional structures that include normal faults whose dip decreases with depth are well known in the West African passive margin. The faults detach on the Aptian-aged Loeme salt layer. Rotation and faulting of the hanging-wall blocks has produced hydrocarbon trap geometries that hold several billion barrels of reserves. Single listric fault systems, including subsidiary faults, are responsible for most structures; however, we have mapped a trend of structures formed by two generations of faulting within the block 0 concession offshore Cabinda, Angola. The resulting geometry of cross-cutting faults has introduced additional trap types not recognized before in the region.