Trapping Mechanism Around Allochtonous Salt in Lower Congo Deep Offshore

Along the coast, the Ceno-Turonian formations (Pinda-Iabe) are affected by normal faults rooted in the Aptian salt, which act as decollement level. These extensional deformations are so important that the Oligo-Miocene formations (Malembo) might directly overlay the autochthonous salt, as the late Cretaceous to Eocene formations are “rafted” basin-ward by the listric faults. An overall extension of about 70km.

The gravity gliding is compensated oceanward by a huge compressional domain involving toe inflation of salt, compressive salt sheets and canopies (locally merging allochthonous bodies) along thrust belts.

In the toe compressive domain, a prolific oil system/play exists around allochthonous salt bodies surrounded by formations of Oligocene and Miocene ages containing good quality reservoirs deposited through turbidite channel systems. With mature source rock complexes around.

Salt structures can play an important role in hydrocarbon trapping. We describe several examples of traps along salt ridges presenting the diversity of traps Lower Congo ridges in a compressive salt tectonic zone. All traps have been tested positive and encountering significant hydrocarbon accumulations, proving traps and petroleum system efficiency.