For the first time since the fall of Saddam Hussein, foreign oil companies will get a chance to work on Iraq's oil reserves when Baghdad auctions off contracts to develop six of its most prized oilfields on June 29-30.
Two undeveloped gas fields are also on offer.
Criticism from within the Iraqi state-run oil industry, pressure on the oil minister, and the terms of the contracts themselves make the deals risky and troublesome, but global oil firms say the potential is tantalizing.
Here are some facts about Iraq's oil industry:
HOW MUCH OIL AND GAS IS THERE?
Iraq is listed as having the world's third largest crude reserves at 115 billion barrels.
That estimate, however, is based on seismic data from nearly three decades ago and some experts believe there could be another 45 billion to 100 billion barrels of recoverable oil.
That could take Iraq's reserves close to top oil exporter Saudi Arabia's estimated 267 billion barrels.
Proven natural gas reserves are 112 trillion cubic feet. Around 60 percent of gas output is burned off because Iraq cannot make use of it. Baghdad has signed a deal with Royal Dutch Shell to stop that in the south.
PRODUCTION REALITY AND ASPIRATIONS
Iraq produces 2.3 million to 2.4 million barrels per day of crude, mainly from the southern fields. That is below the 2.5 million barrels per day produced before the invasion.
Iraq has an ambitious plan to boost output over 6 million bpd in five years. The first contracts are expected to add 1.5 million bpd. A second round of tenders later this year for 11 undeveloped fields could add another 2.5 million bpd.
A LITTLE HISTORY
Iraq's oil has been coveted by foreign powers for decades.
When Britain ruled Iraq in the early 20th century, oil was handed as a monopoly to the Iraq Petroleum Company (IPC).
A nationalist military officer, Abdul Karim Qassim, seized power in a 1958 coup and in 1961 took 99 percent of concessions away from the IPC. In 1972, Iraq nationalized the rest.
The early years of Iraqi oil production were glory days, but Saddam then went to war with Iran in 1980.
Around 60 percent of oil facilities in the south and center were damaged in the 8-year war. The damage was aggravated in the first Gulf War that followed Saddam's 1990 invasion of Kuwait, and subsequent sanctions on Iraq led to further underinvestment.
The 2003 U.S.-led invasion led many to believe that Iraq's vast reserves would soon be on offer to global oil firms.
Sectarian warfare and insurgency, however, kept that day at bay, while theft, sabotage and continuing neglect caused further decay in the industry's infrastructure.
FIRST FOREIGN DEAL?
The contracts on offer on June 29-30 are not the first foreign oil deals since the fall of Saddam, but they are the first to be put out to competitive tender.
Last year, Baghdad revived a $3 billion Saddam-era project with the Chinese National Petroleum Company (CNPC) to develop the al-Ahdab oil field in south-eastern Wasit province.
The government turned the deal into a fixed-fee contract, from the production-sharing accord signed by Saddam.
Russian company LUKOIL has also lobbied Baghdad to resuscitate an old agreement, signed with Saddam, to develop the super giant West Qurna oil field. LUKOIL is less willing to give up the production-sharing terms coveted by big oil firms.
In the meantime, the government has invited Italy's Eni, Nippon Oil of Japan to bid to develop the Nassiriya oilfield.
In Iraq's north, the semi-autonomous Kurdistan Regional Government has struck deals with around 30 companies. But the central government has labeled those agreements illegal.
Kurdistan and disputed areas claimed by the Kurds may hold 65 billion of Iraq's reserves. But the Shi'ite Arab-led government in Baghdad and Kurdish authorities are embroiled in a bitter, potentially explosive standoff over oil, land and power.
The central government gave the go-ahead on June 1 for 100,000 bpd of Kurdish oil to be exported from two fields, Tawke and Taq Taq -- developed by Norway's DNO International, Turkey's Genel Enerji, and Swiss firm Addax Petroleum.
But, while allowing the exports to go ahead, Baghdad has refused to recognize the legality of the production sharing agreements the Kurds signed with the companies. That has made it unclear how the firms will be paid.
A new hydrocarbon law has languished in parliament for years, hostage to the bickering between Arab and Kurds. The law is supposed to resolve divisive issues such as control of oil and gas reserves and how the wealth they generate should be shared between central government and the provinces.
International oil firms say they remain concerned about security in Iraq, despite a sharp fall in violence.
Suicide and car bomb attacks by Sunni Islamist al Qaeda or other violent groups remain common, and providing security is a significant operating expense for any foreign investor in Iraq.
Kidnapping for ransom has also become a growth industry.
(Sources: U.S. Energy Information Administration, Reuters)
(Reporting by Michael Christie in Baghdad; Editing by Missy Ryan and Simon Webb)