Exploration activities commenced in 1990. As at January 2008, 33 exploration wells have been drilled, resulting in 18 discoveries, some of which have been tested at flow rates above 21,000 barrels of oil per day.  Further exploration drilling is taking place.

The initial discoveries were the El Merk Field and El Merk East Field in Block 208. These were followed by the discovery of three major oil fields in Block 404a: Hassi Berkine (HBN), Hassi Berkine South (HBNS) and Ourhoud. Later discoveries were the so-called satellite fields in Block 404a, covering some 10 fields.