According to the NIOC news portal, each company conducted surveys on the field for about six months.
DNO handed in its findings last week while Gazprom and PTTEP reportedly presented their master plan on Monday.
According to Ali Abbas Lorki, director of the Changuleh oilfield, the surveys will be examined by separate technical teams at the NIOC and "once preliminary assessments are over, NIOC's Reservoir Management Committee will make a decision on developing the field."
"Plans are in place to develop the field in two phases," Lorki said, noting that in the first phase, which is scheduled to last 36 months, production will reach 15,000 barrels per day by drilling four and repairing two wells. Laying a 100-kilometer pipeline and installing a gas-oil separation unit are also part of the first development phase, Financial Tribune reported.
The second phase calls for drilling 13 wells along with extending the pipelines, with the field’s output to increase to 50,000 barrels a day.
The oilfield is located near the Iraqi border in the western Ilam Province. It is estimated to hold over 3 billion barrels of oil in place. Officials forecast that production could reach as high as 75,000 barrels per day.
The field was discovered nearly two decades ago but development has been next to nothing.
Changuleh was discovered in 1999 as a result of explorations conducted by a consortium comprising Russia’s Lukoil and Norway’s Statoil. The field's development is estimated to require an investment worth $2.2 billion.
Officials in Tehran have already speculated that Changuleh could be linked to another major nearby field named Azar which is believed to be shared with Iraq's Badra field.
According to Gholamreza Manouchehri, the deputy for development and engineering at the NIOC, Iran is also studying a proposal by DNO to develop Hengam oil and gas field in the Persian Gulf, the only shared field between Iran and Oman.
Manouchehri noted that DNO is interested in developing Hengam based on a practice known as “unitization”—the joint development of a hydrocarbon reservoir extending across two countries—based on which the two sides split production and profit.
Iran is pushing for major deals with multinationals to raise crude production. It is now pumping close to 4 million barrels a day, a level last seen before the tightening of sanctions in 2011.