2D Petroleum System Modeling of the Mandawa Basin, Southern Coastal Tanzania

Abstract

In this study the seismic interpretation was performed by using 2D seismic data combined with well data and literature information with Petrel Schlumberger software version 2013 in order to understand the stratigraphy and structural setting of the Mandawa Basin, southern coastal,Tanzania. PetroMod 2013 petroleum system modeling software has been used for 1D and 2D petroleum system modeling by integrating geophysical. geochemical and geological data in order to understand the petroleum system of the study area.The results indicate that the source rocks in the basin are at different levels of maturity ranging from immature, mature to completely overmature for hydrocarbon generation. In addition, the 1D results indicate that the source rocks in the basin have the capability of generating both oil and gas. The timing of hydrocarbon generation, expulsion, migration and accumulation commenced from early to mid Jurassic and possibly continues up to the present day. The generation of hydrocarbons is considerably affected by the onset of uplift and erosion events as reflected in the models results. 2D Petroleum system modeling predicts oil accumulations in the pre-salt reservoirs (Mbuo sandstone), and migration of the oil to the reservoirs is just a short distance by vertically downward movements and laterally within the reservoirs until the potential traps are reached. However no oil accumulations are predicted by the model in the post-salt reservoirs due to the presence of an effective seal above the source rocks. A significant number of accumulations as predicted by 2D models occurred in the late Jurassic to early Cretaceous.