Engineers are seen at the Naher al-Umran gas refinery, in the el-Dir district, some 40 kms north of the southern city of Basra, on July 17, 2009. The trade union representing workers of Iraq's state-owned Southern Oil Company (SOC) threatened to prevent exploitation of one of Iraq's biggest oil fields - Rumaila oil field in southern Iraq - by energy giants BP and CNPC. AFP PHOTO / ESSAM AL-SUDANI