Being in an act of parliament to provide for the management of petroleum operations, to regulate and promote petroleum exploration, development, and production to regulate the licensing and participation of commercial entities in petroleum operations to provide for proper supervision of petroleum operations, to promote the participation of Sierra Leone in the petroleum industry.
Being in an act of parliament to provide for the management of petroleum operations, to regulate and promote petroleum exploration, development, and production to regulate the licensing and participation of commercial entities in petroleum operations to provide for proper supervision of petroleum operations, to promote the participation of Sierra Leone in the petroleum industry.
The Sierra Leone basin forms part of the West African Transform Margin and is made up of complex strike-slip faulting. The basin consists of a continental shelf and a steep slope (Sulima slope plateau) with rotated fault blocks seen on the slope and gradually stepping down into the deep-water basin. The Sulima slope seen on the northern part of the area is an expression of a series of horsts and grabens formed by wrench tectonics as the Sierra Leone transform system intersects the African continental mass.
The shelf break is characterized by a steep slope with several submarine canyons which cut deeply into the continental shelf down to the abyssal plain. A series of transform fault systems exist along the margin but the main transform fault system that affected the basin is the right-lateral Sierra Leone transform fault system which forms a series of an echelon strike-slip and dip-slip faults with associated folds. In the deep-water part further from the coast, normal faulting during the Atlantic rifting event produced grabens and half-grabens of probably Albian-Aptian age.
The structural architecture of the basin is described in three phases, namely the pre-rift, rift, and post-rift (passive margin phase). The pre-rift phase mainly encompassed the faulting of the pre-rift strata throughout the Palaeozoic to Jurassic times with associated volcanic activities.
The rift phase started in late Jurassic/early Cretaceous time, coincident with the tectonic subsidence of the stretched continental crust, caused by the upwelling of the asthenosphere. Extensional faulting is associated with extrusive igneous activity and continental siliciclastic deposition took place in the graben. This Phase was active from Aptian to Turonian with fluvial/lacustrine conditions trending to shallow marine as Africa was finally separated from South America.
Sub-aqueous and sub-aerial erosion took place on the shelf and slope in the mid-Cretaceous time and is evident on seismic data by the occurrence of a regional unconformity which persisted as a surface of erosion until the Santonian time. The progression of seafloor spreading introduced a late Cretaceous transgression which advanced shoreward over the mid-Cretaceous erosional surface.
The marine deposition was continuous oceanward from late Albian to the end of Cretaceous time. Onlap of marine siliciclastic and some carbonate deposits are seen on the mid-Cretaceous unconformity.
The hydrocarbon potential of the basin was known when the Venus B-1 discovery well was drilled. A series of other discovery wells confirmed that there is an established petroleum system within the basin.
| Survey Name | Data Type | Data Volume |
|---|---|---|
| Lukoil Reprocessed | 3D | 1000 sq kms |
| Repsol 2004 PSTM | 3D | Circa 4150 sq kms |
| Anadarko 2009 3D Survey (PSDM) | 3D | Circa 4150 sq kms |
| Sierra Leone 3D (Blocks 3; 4 and 5). 2008-2011 | 3D | Circa 4150 sq kms |
| Sierra Leone 3D (Blocks 4 and 5). 2008-2014 | 3D | Circa 4150 sq kms |
| Sierra Leone 3D (Blocks 3; 4 and 5 Extension). 2008-2014 | 3D | Circa 4150 sq kms |
| Sierra Leone Mega-Merge (Fusion) | 3D | Circa 4150 sq kms |
Data for all the six (6) recent wells and the two wells drilled along the margin in the 1980s have been released by Petroleum Directorate. PDSL in association with TGS and PVE Consulting has created a digital well database.
All the data is available to review in our data rooms in Freetown, London and Houston.
The 2009-2013 well data are available to license for the first time along with the Mabesi 3D PDSM seismic dataset, which covers three of the recent deepwater discoveries by Anadarko.
| Name | Year | Operator | Well Status |
|---|---|---|---|
| A-1 1982 | 1982 | Mobil | Oil Shows |
| A-1 1985 | 1985 | Amoco | Oil Shows |
| Venus B-1 | 2009 | Anadarko | Discovery |
| Mercury-1 | 2010 | Anadarko | Discovery |
| Mercury-2 | 2012 | Anadarko | Appraisal |
| Jupiter-1 | 2012 | Anadarko | Discovery |
| Djembe-1 | 2012 | Talisman | Water wet | Savannah-1X | 2013 | Lukoil | Discovery |
20 Mandalay Street
Kingtom
Freetown
Sierra Leone
Monday – Friday:
8:00 – 17:00
Saturday: closed
Sunday: closed
+232 76 41 39 12
info@pd.gov.sl
