Assessment of structural evolution of the southern kilombero rift basin, Tanzania: Implications for hydrocarbon potential
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Date
2023
Authors
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Publisher
The University of Dodoma
Abstract
In recent years, rift basins, including the southern Kilombero basin, have gained significant interest due to the discovery of oil in the East African Rift System, include the Albertine graben in Uganda and the Lokichar basin in Kenya. Although the southern Kilombero rift basin has been little studied using few widely spaced 2D seismic lines, there is a lack of detailed information regarding the structural pattern and kinematics, as well as their relationship with the southern Kilombero rift border fault. Therefore, this study focuses on the structural evolution of the southern Kilombero rift by conducting morphostructural and paleostress analysis to establish important fault parameters, including the current rift kinematics. The study uses SRTM-DEM, fieldwork, literature reviews, seismic interpretation and sandbox modeling in order to simulate the faulting sequences and their pattern with time. The results of the morphostructural analysis have revealed that the southern Kilombero rift border fault is a nearly 100 km long, symmetrical rift segment characterized by vertical displacement ranging from 250 m to 1300 m. The current seismic activity in the area is controlled by NNW–SSE trending normal faults. The analysis and interpretation of the results of the modeled stress tensor indicate that the stress regime is predominantly extensional being characterized by normal faulting and a horizontal minimum stress axis of approximately (Shmin) 060˚, suggesting that the southern Kilombero rift is an oblique rift. The sandbox model reveals that the southern Kilombero rift basin is transitioning from a half-graben into a full-graben, signifying an essential structure for hydrocarbon accumulation, fluid migration and preservation. During syn-kinematics rifting, the extension of the border fault led to the formation of numerous minor structures, increased accommodation space, relay ramps, en-echelon fault segments and intrabasinal structures. These structures contribute greatly to the basin’s evolution. Correlation between the 2D seismic data and the sandbox model suggests that sandbox modeling outperforms seismic data in identifying and interpreting complex, minor and structural features in subsurface geology. The discovery is anticipated to motivate geoscientists to explore more potential hydrocarbon resources in the future for economic gain.
Description
Dissertation (MSc in petroleum geosciences)
Keywords
hydrocarbon, rift basins, Morphostructural analysis
Citation
Richard, G. (2023) Assessment of structural evolution of the southern kilombero rift basin, Tanzania: Implications for hydrocarbon potential (Master’s Dissertation). The University of Dodoma, Dodoma