Abstract: The 1911 Quadrant Offshore Namibia; Exploration in a Virgin Basin

Erik Holtar, Arne Forsberg

As a result of the first licensing round in independent Namibia, the Namibian authorities in 1992 awarded five offshore licences to five different companies or groups of companies. Licence no. 001 was awarded in 1992 to a group consisting of three Norwegian oil companies, Norsk Hydro, Saga Petroleum and Statoil, with Hydro as the operator. Somewhat later Bow Valley Energy (now Talisman Energy) farmed in.

Since 1992 a seismic survey of 7200 km has been acquired over the licence area that covers 11.619 sq km of the Walvis basin. This basin was undrilled until the 1911/15-1 well was finished at a depth of 4586mRKB in early 1994.

The sedimentary succession of the 1911/15-1 well reflects a depositional history that postdates the Neocomian Etendeka plateau basalts found onshore Namibia. After the onset of the drift phase in late Hauterivian times, the Walvis basin subsided and eventually a marine transgression took place. Shallow marine platform sedimentation then prevailed until an Albian tectonic event resulted in complex block faulting and the formation of several sub basins. Subsequent volcanic activity created a series of volcanic centres localised on the Walvis Ridge bathymetric feature. In early Late Cretaceous the Southern African craton was uplifted relative to the shelf, leading to the formation of large scale westward prograding wedges. Later sedimentation largely followed the evolution of a passive continental margin, responding to relative sealevel changes and paleoclimate.

A stratigraphic breakdown of the Northern Namibian offshore is proposed, and compared to South African and Angolan nomenclature.

AAPG Search and Discovery Article #90956©1995 AAPG International Convention and Exposition Meeting, Nice, France