AGC was created in 1993 following an agreement that was signed in Dakar on October 14, 1993 by the Governments of Senegal and Guinea-Bissau. It is a joint committee that was set up by the Governments of Guinea-Bissau and Senegal to administer the maritime zone between the two countries.
The “Profond Bloc AGC” includes the deep waters of the two sections known as “Cheval Marin et Croix du Sud”. The “block” has a surface area of 9.838 km² and lies in waters from 50 to 3,500 meters deep. Senegal and Guinea-Bissau are two countries that are linked by geography and history. Senegal is a former French colony, while Guinea-Bissau was colonized by the Portuguese.
After the two countries became independent (1960 for Senegal and 1973 for Guinea-Bissau), they started negotiations to determine their common maritime border through the Franco-Portuguese Agreement in 1960.
After lengthy negotiations that were marked by disagreements as to the existence of the Franco-Portuguese Agreement and anxious to further develop good neighborly relations and cooperation between the two countries, the Governments of the Republic of Guinea-Bissau and the Republic of Senegal agreed to establish an international agency for a common exploitation of the maritime zone between the 268º and 220º Azimuts starting from the Cape Rox intersection between the Senegal-Guinea-Bissau land border and the coast.
The exploration of the AGC area began in 1958 when the area was separately awarded to COPETAO ( Companie des Petroles Total Afrique de l’Ouest) in Senegal and the company EXXON in Guinea Bissau. Initial exploration focused on salt diapir related structural traps and resulted in the discovery of the Dôme Flore (1967) and Dôme Gea (1971) oil accumulations.
ln 1991, Casamance Petroleum Ltd took the Dome Flore area and acquired a 3D seismic (300 sqkm), over Dome Flore and Dome Gea. The licence expired in 1994, and the area was subsequently relicensed to Pecten, who in 1996 drilled a shallow exploration well on the eastern flank of Dome Gea, Boabab-1. This well encountered many levels with oil shows.
From 1997 to 1999, the AGC undertook speculative seismic projects and a vast promotion of the deep water blocks.
As the result of the promotion, two permits for hydrocarbon exploration in the deep areas (Cheval Marin and Croix du Sud) were respectively awarded to AGIP (ENI) and Fusion Oil & Gas NL in 2001.
These two companies undertook important 2D and 3D seismic, magnetic and gravity surveys, geochemical and geological studies in their respective blocks.
The interpretation of the newly acquired dataset identified many prospects in these two blocks.
In February 2016, Woodside Energy (Senegal) Pty Ltd entered into an agreement with Impact Oil & Gas AGC Ltd to acquire a 65% participating interest in a Production Sharing Contract (PSC) and associated joint operating agreement in the AGC Profond block.
The Joint Development Zone between Senegal and Guinea-Bissau is part of the MSGBC passive margin basin characterised by a working petroleum system certified by the heavy oil discovery in Oligocene foraminiferite. The Oligocene reservoir is formed by planctonic and benthic foraminiferites cimented by sparite with intercalation of lenticular limestones.
GEOLOGY OF THE SEDIMENTARY BASIN
Sedimentary Basin of Senegal occupies the central part of the great West African coastal basin (MSGBC), which extends the shield Reguibat north to the rupture zone of Guinea to the south. Senegal sedimentary basin is formed by the sub-basin Dakar – Banjul, the largest portion of Senegal basin, which extends from 16° N to 13° N and the sub-basin Casamance-Bissau which extends between the parallel 13° N and Guinea-Bissau.
Each sub-basin has a different sedimentary and tectonic history that in part reflected by the intensity of the activity halokinetic. The area of the AGC covers the central part of the sub-basin Casamance-Bissau, which is characterized by intense tectonic saliferous causing ductile and brittle deformation in the vicinity of major salt domes Dome Flore and Dome Gea Iris Dome.
Several clastic and carbonate reservoirs have been encountered in wells drilled in the area between 1958 and 1996 wells.
Several of them have proven to be excellent reservoirs, with a porosity between 20% and 50%. Similarly, the 3D seismic data have revealed stratigraphic phenomena interpreted as significant deposits of Upper Cretaceous turbidites which are generally excellent reservoirs by analogy with other deep-water basins of Africa west.