Abstract:

Polygonal faults have been documented in many sedimentary basins. The faults have very detective properties of Polygonal systems, very complex fault intersection geometry with through ranging from meter to 100m, 0.5 to 1.5km in length. The faults was proposed to be generated by episodic dewatering of thick shale succession and the overpressured pore fluid which restricted in fine-grained sediments. The widespread of Polygonal faults (~500km2) have been observed in offshore Cameroon, with the water depth range from 940m to 1750m. Polygonal faults mainly developed in Tertiary sequences, in the slope 1, which is characterized as low amplitude and discontinuous reflections. These faults fall into two tiers: the lower tier in the unit 5 and 6, the upper tier in the unit 10. The occurrence of Polygonal fault has important implication for the seal potential. However, further study need to be carried on to confirm the role of seal, particularly for the lower reservoir unit