Band-e-Karkheh oil field is located at the southwest side of Mehr Block, 20 km to the south-west of Ahwaz oil field & its trend is from northwest to southeast. The field structure is an extended anticline shape with the area of 35×4 km2. Almost one-sixth of its structure has elongated toward the northwestern border of Mehr Block. The ridge slope of structure is gentle and its maximum slope is 5 to 6 degrees. The first, second, and third layers of Ilam formation contain oil. Recoverable oil is estimated about 110 M barrels it is heavy oil (API: 24) in Ilam formation.