Three Russian firms have submitted plans to develop Iran’s oil and gas fields as more foreign investors line up to sign deals in Iran’s energy sector.

Russia’s Zarubezhneft, Gazprom Neft as well as Lukoil submitted their plans to the National Iranian Oil Company (NIOC) after signing memoranda of understanding (MoU) with the state oil company after nuclear-related sanctions against Tehran were lifted last year.

State-owned exploration and production company Zarubezhneft, which has upstream interests in Vietnam submitted a plan to increase the recovery rate of crude from the Aban and West Paydar fields, which straddle the Iran-Iraq border.

The firm is also interested in the Shadeghan and Rag Sefid fields in the southern oil-rich Khuzestan province and signed an MoU in July to conduct technical studies on the concessions.

Shadeghan discovered in 1968 produces around 69,000 barrels a day of crude, while Rag Sefid discovered in 1964 is estimated to hold 16.5 billion barrels of oil. The National Iranian South Oil Company, which oversees development of the field has used natural gas injection to enhance crude recovery.

Gazprom Neft, which signed an MoU with the NIOC in December submitted plans to develop the Changouleh and Cheshmeh Khosh fields located in Iran’s Lorestan province, which lies on the Iraqi border.

Norway’s DNO submitted a plan to develop the Changouleh field, which was discovered in 2005 along with the adjacent Azar field by a consortium of Norwegian energy firm Statoil as well as Lukoil.

The Azar concession is shared with Iraq, where it is known as Badra and along with Changouleh, they are estimated to hold 3.5 billion barrels in reserves.

Lukoil has also submitted a plan to develop the Bangestan reservoir of the Ahvaz field, which is being considered for enhanced oil recovery to raise production by five to eight percent.

Russian firms are also in advanced discussions to develop other concessions such as the massive Farzad B gas field as Iran looks to invite foreign partners to help recover its pre-sanctions output and market share.