PETROLEUM GEOLOGY AND EXPLORATION POTENTIAL OF RUKWA BASIN IN EAST AFRICAN RIFT SYSTEM

Since the breakthrough in oil and gas exploration in the Albertine Basin, the Western Branch of East African Rift System (EARS) has become a hot spot for research and exploration. Among the basins in EARS, the Rukwa Basin is the one with thickest deposits but low exploration degree. It is a pull-apart half graben characterized by strike-slipping, located in the Tanganyika-Rukwa-Malawi transform zone. There are three sedimentary sequences in the basin, i.e. the Permian-Triassic Karoo Super-group, the Cretaceous-Paleogene Red Sandstone group and the Pliocene-Pleistocene Lake Beds respectively. The maximum thickness of total deposits may reach 11 kilometers with great horizontal variation. There are two potential source rocks, the Karoo (coal and black shale) and the Lake Beds (lacustrine mudstone). Good reservoir-seal combination and good hydrocarbon accumulation conditions with well developed fracture system has been found in the southeast, the favorable exploration area of the basin. Source rock is the main geological risk of the exploration in this basin.