Tectono-sedimentary evolution of the offshore hydrocarbon exploration block 5, interpreted from 2d seismic dataset

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University of Dar es Salaam
Using four (4) 2D seismic profiles and one (1) well data across Block 5, offshore Northern Tanzania, tectono-sedimentary evolution and hydrocarbon potential of Block 5 have been assessed. Four seismic units have been used in the study to show the link between the tectonic events in terms of structural styles, sedimentation and hydrocarbon potential in Block 5. The results reveal that in Early to Late Jurassic Block 5 was affected by the break-up of Gondwana and the drifting of Madagascar evidenced by patterns of sediments and structural features. Sediments in unit 2 are characterized by chaotic and discontinuous reflectors indicating a possible transitional setting following the breakup of Gondwana. Furthermore, the results show a distinctive difference in the accommodation space created by the early rift faults. Early depocenters (WI and W2 and NW-SE trending) were then filled with Middle to later Jurassic sediments but projected to span for short time due to the tectonic influence that prevailed. From the Late Cretaceous, Block 5 sits in more stable subsiding sag as consequence of the high thermal subsidence. This period was marked by seismic unit 3 and displayed continuous parallel reflectors with few markable faults. Seismic unit 4 with high wavy and sub parallel reflectors represents the late Post-rift high sedimentation occurred after Middle-Eocene Uncoformity. Hydrocarbon Control in the Block 5 is the function of the interplay between the tectonics and the sedimentation. For example the Jurassic and Cretaceous depocenters are filled with source rock caped with regional shale while the structural reactivation (local inversion) in Cretaceous (Unit 3) and post-Eocene strike-slip (F4) structural feature can be grouped as major predictive structure for hydrocarbon in Block 5.
Available in print form, East Africana Collection, Dr. Wilbert Chagula Library, Class mark (THS EAF QE511.S46)
Sedimentation and deposition, Plate tectonics, Geology, structural
Seni, E. J. (2017) Tectono-sedimentary evolution of the offshore hydrocarbon exploration block 5, interpreted from 2d seismic dataset, Master dissertation, University of Dar es Salaam, Dar es Salaam.