Block 406a is located in the prolific Berkine Basin in southeast Algeria. The block contains two fields discovered in the 1990s - Rhourde Khrouf (RKF) and Ourhoud. The Ourhoud field is unitised to Blocks 404a, 405 and 406a. Ourhoud was brought onstream in December 2002, and is now recognised as the second largest oil field in Algeria behind the giant Hassi Messaoud field. The Rhourde Khrouf field reached peak production of 20,440 b/d in 2003.