Hassi Messaoud (häs´sē mĕs´säōōd´) [Arab.,=blessed well], town, E Algeria. Formerly a watering hole in the Sahara desert, Hassi Messaoud rose to prominence with the discovery of oil in 1956. In 1979, oil refining expanded greatly. A refinery is located in the town, and pipelines carry oil to Skikda, Algiers, Bejaïa, and Arzew. By the early 1980s half of Algeria's total oil production came from the field.