The Taoudeni Basin is a vast sedimentary basin of 1,500,000 square km, a third of which is located in Mauritania, dating from the end of the Precambrian to the Paleozoic. It is a large intracratonic basin that appears to have been formed in response to the Pan-African Orogeny. The basin started in the Infracambrian and continued to develop during the Paleozoic until the Carboniferous.
The Taoudeni Basin has witnessed two important exploration periods:
- In the early 1970s, Texaco and Agip have each allocated a block, and carried out 2D seismic surveys and then respectively dug wells Abolag-1 and Ouasa-1. The Abolag-1 well crossed two reservoir levels, one of which (middle Infracambrian stromatolite limestone) produced the equivalent of 480,280 cf per day of gas during a two hours’ DST (Drill Stem Test).
- The second period began in 2004, when exploration resumed with Total, Repsol, Sipex and SMH. It has yielded greater 2D seismic coverage and the drilling of the Atil-1 (Ta8-1), Ta7-1 and Ouguiya-1 wells which have revealed some gas shows and low yields.
Two petroleum systems have been identified:
- Paleozoic petroleum system, related to good quality Silurian and Devonian source rocks and Ordovician reservoirs.
- Neo-Proterozoic petroleum system, related to source rocks of interstratified Infracambrian black shales and reservoirs of fractured limestone with stromatolites and sandstones.
Exploration wells: Abolag-1; Ouasa-1; Atil-1 (Ta8-1); Ta7-1 and Ouguiya-1.