Iraq will resume searching for oil this week for the first time in two decades in the hope of finding vast reserves untapped because of sanctions and war, says the country's Oil Ministry.
Iraq has 115 billion barrels of proven oil reserves, the third biggest in the world, but the government believes the country's actual oil reserves may be three times as high.
Ministry spokesperson Asim Jihad says it has trained three teams of geophysicists, geologists and engineers and will begin exploration in the Gharraf field in Nassiriya in southern Iraq on Friday.
Mr Jihad says Iraq has used only a fifth of its 500 possible oil-producing sites and it needs to explore more to try to confirm potential reserves.
In April, Deputy Prime Minister Barham Salih said he had seen estimates from "reputable companies" that put Iraq's oil reserves at 350 billion barrels, which would put the country ahead of Saudi Arabia.
Saudi Arabia is ranked first in the world with proven reserves of 264 billion barrels, followed by Iran with 137 billion and Iraq with 115 billion.
Iraq needs huge amounts of investment to boost oil output and rebuild the country after years of sanctions and war.