###### Abstract  
In this paper, we study the structural characteristics and sedimentary filling differences of the passive continental margin basins of East Africa and establish hydrocarbon accumulation models in different basins. In the research process, the research methods of prototype basin and lithofacies paleogeography restoration, oil and gas reservoir anatomy, two-dimensional seismic data interpretation, etc. The passive continental margin basins in East Africa are divided into four types of passive continental margin basins, namely \"rifted type,\" \"depressed type,\" \"faulted depression type,\" and \"reformed delta type,\" based on the three prototype stages of intracontinental aborted rift, intracontinental-intercontinental rift, and passive continental margin basin, and the difference in sedimentary filling thickness between rift and depression periods. Finally, the accumulation models of different types of basins are established, and the favorable accumulation combinations and future exploration directions are discussed.  
passive continental margin basin; lithofacies paleogeography; basin structural architecture; hydrocarbon accumulation model; deepwater hydrocarbon exploration +
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the periphery of Madagascar southwards, mainly including Obbia, Coriole, Juba, Lamu, Tanzania, Rovuma, Angoche, Zambezi, Morondava, and Majunga Basins, with a total sedimentary area of more than 3.7 \(\times\) 10\({}^{6}\) km\({}^{2}\), of which 1.51 million km\({}^{2}\) is under 200 m water depth. These basins have a clear two-layer structure: the lower rift sequences include the Upper Carboniferous, Permian, Triassic, and Jurassic, mainly filled with terrestrial sediments; the upper depression sequences consist of the Cretaceous and Cenozoic strata, all of which are filled with marine sediments.  
Exploration activities along the coast of East Africa started in the 1950s. Drilling activity began in 1958, and until 2010, a total of 232 wells had been drilled. However, the drilled wells in this stage were limited to onshore and shallow-water regions with a depth of less than 100 m, and the success rate of drilling was extremely low. A total of 33 large and medium-sized oil and gas fields were discovered in onshore and shallow-water areas in the Obbia Basin, Coriole Basin, Juba Basin, Zambezi Basin, Tanzania Basin, and Rovuma Basin, with a total of 2 P recoverable reserves of 1.43 billion barrels of oil and 48 TCF of natural gas. The Tsimiroro and Bemoolanga heavy oil and oil sand deposits were found onshore in the Morondava Basin, with estimated geological reserves of 2 billion barrels and 11 billion barrels, respectively. In August 2010, drilling began in the deep-water region, and 25 large and medium-sized gas fields were discovered in Blocks 1 and 4 of the Rovuma Basin and Blocks 1, 2, 3, and 4 of the Tanzania Basin, with a total of 143 TCF of new 2 P recoverable reserves, all located in deep and super-deep-water regions. Despite this, the exploration degree in the area is still very low, with all discoveries concentrated in the northern part of the Rovuma Basin and the slope of the Tanzania Basin. There are only 15 blocks with  
Figure 1: Distribution map of passive continental margin basins in East Africa.  
exploration wells at water depths greater than 200 m, with a total area of 130,000 km\({}^{2}\), accounting for less than 10% of the entire deep-water exploration area (Figure 2).