Authors : Nick Lausaire Nombo-Makaya and Chen Hong Han
Abstract: Lower Congo Basin located at the west central coastal part of Africa, which covers 115,000 km2 out to water depths exceeding 3,500 m, presents Cretaceous pre and post-salt trend. The trend stretches to 350 km along the coastline at water depths <200 m from the Republic of Congo to central Angola. Conduits for oil migration generated from mature Pre-salt source rocks would be along fault planes and salt flanks. In this Basin, we distinguish the Vandji structure, which is the study case. And from the structure, reservoirs were highlighted by 3 wells: A, D and E. Well B and C show aquifers in Chela and Vandji Formations. Well D show aquifers in Chela and Vandji formations, but it shows some hydrocarbons in detrital intercalations included in Sialivakou Marls. In well E, Vandji formation is absent, probably eroded during the basement rising. The pre-salt petroleum system in Vandji-Conkouati structure, consists of two main separate reservoirs with oil accumulations (Jurassic basal sandstones of the Vandji formation) associated with gas caps (aptian Chela sands formation), a source-rock (Sialivakou marls), which act also as a cap-rock. The hydrocarbon migration is done along faults and Vandji and Chela formations. The trapping process could be caused by sealed faults.
Nick Lausaire Nombo-Makaya and Chen Hong Han, 2009. Pre-Salt Petroleum System of Vandji-Conkouati Structure (Lower Congo Basin), Republic of Congo. Research Journal of Applied Sciences, 4: 101-107.