Geological Structure and Prospects of Oil and Gas Bearing at the Continental Margin of Tanzania

On the continental margin of Tanzania two big sedimentary basins - Tanzanian and Rovuma are distinguishing. Within the Tanzanian basin the following six subbasins from north to south along the littoral are distinguishing: Tanga, Pemba-Zanzibar, Latam, Rufidji, Mafia and Mandava. The big part of Tanzania is situated on the East African plateau. Sedimentary cover of the basin is presented by Phanerozoic deposits of 7-10 km thickness on the Archean basement. The Rovuma basin consists by two blocks Mrvara and Linde. The basin is characterized as a passive continental margin with a complex tectonic history. Rovuma basin is the principal gas bearing basin in the country. The formation of gas accumulations on the southeastern continental margin of Africa is associated with the spread of the Karoo complex, dated to the Permian-Triassic age. Analysis of more than 25 discoveries gas fields on the Tanzanian continental margin results to conclusion that all discovered gas fields gravitate mainly to the western side of the blocks. Large gas accumulation is marked in the deepwater areas, on the slope. Moreover, large gas discoveries have been made in the south of Tanzania. As far as advancement forward to the north the quantity and reserves of gas fields reduced. At the north of Tanzania gas accumulations have not been found, but oil accumulations have been noted.