East Africa Transform Margin The View from Tanzania and Madagascar Richard Higgins and Mark Sofield 10th PESGB/HGS Conference on African E & P, London, September 7-8, 2011 Acknowledgements Legal Notice: No representation or…
Agenda Location & Recent Activity Regional Tectonic Elements Influence on Petroleum System Elements Summary MOZAMBIQUE TANZANIA 2
Recent Activity East Africa Multiple 2D and 3D Seismic surveys acquired since 2005 Drilling campaigns conducted in Tanzania (Ophir/BG) and Mozambique (Anadarko et al.) in 2010/2011 Pweza Gas Discovery Seven gas discoveries Chewa…
Recent Discoveries Tanzania Strong relationship between seismic amplitude anomalies and gas-bearing reservoirs. Nearby targets with similar seismic characteristics now substantially de-risked. Further 3D seismic surveys have…
Regional Tectonics Karroo continental rifting Development of passive margin successor basins Late Carboniferous to Early Jurassic East African Tertiary Doming Gondwanaland break-up Initial opening 180Ma (NW-SE) N-S opening from…
Tanzania - Gravity Significant change in gravity signature across the Davie Fracture Zone (DFZ), B4 Seagap Fault Zone separating continental and oceanic crust. B3 Continental crust dominated by N-S trending anomalies that…
Seagap Fault Zone Triassic/Jurassic Rift Faulting Generation of N-S Seagap Fault Zone during Jurassic to Aptian Reactivation of rift faults Oligocene onset of reactivation (transtensional in above example) Pliocene reactivation…
Seagap Fault Zone Transtension Transpression 8
Seagap Fault Zone SEMBLANCE A Riedel A B Restraining B Bend C C D Releasing Bend D Modified from Mikenorton, Wikipedia, 2009 9
Tanzania - Onshore From Nicholas et al., (2007) From Nicholas et al., (2007) 10
Structural Control on Reservoir Input S N East Pande 11
Reservoir Quaternary Holocene Pleistocene Quaternary and Tertiary Tertiary Mesozoic Tertiary and Cretaceous Cretaceous Lower Cretaceous Cretaceous and Jurassic Jurassic Lower Jurassic Jurassic and Triassic Triassic Lower…
Madagascar - Gravity NE-SW rift faults NW-SE transfer zones Deep structural control on sediment input and fault linkage 13
An East African Deepwater Cretaceous Source Rock Duvalia Formation (Berriasian to Aptian shallow to deep marine 249 Thin Aptian Shales MB facies) in Southern TOCs up to 9% Morandava Basin potential for an Excellent quality Lower…
An East African Deepwater Cretaceous Source Rock Songo Songo Winganyongo & Lower Cretaceous (contamination) Ruaruke SS 5 TOCs up to 11% Lower Cretaceous SS7 TOC up to 5% Samples measured SS8 TOC up to 1.57% TOCs of 18%…
Summary Recent discoveries to the west of the DFZ herald the start of an exciting period of hydrocarbon exploration offshore East Africa. Tanzanian acreage appears have been significantly influenced by strike slip tectonics…
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