"Following two earlier contracts with two Russian oil companies, Iran has signed a memorandum of cooperation in oil and gas industry with a third Russian firm. Given the newly-signed agreement, the number of Russian companies active in Iran’s oil and gas industries has reached a total of three. Previous deals were sealed with Zarubezhnefta and Lukoil companies while the third one Tatneft, a Russian vertically integrated oil and gas company with headquarters in the city of Almetyevsk in the Republic of Tatarstan... on Saturday morning, NIOC Managing Director Ali Kardor and CEO of Tatneft Nail Ulfatovich Maganov signed the deal to conduct developmental studies in Dehloran oil field. The agreement marks the first contract signed between NIOC and the Russian firm and it mainly deals with increasing recovery factor of the Iranian field." (Mehr News, "Iran inks oil deal with Russia's Tatneft," 10/8/2016).
"Iran signed a deal reportedly worth up to $1 billion with Russia's Tatneft on Sunday to develop an oil field, a rare example of new foreign investment into the oil and gas sector of a country under ever tighter economic sanctions... The president of the southern Russian republic of Tatarstan, the home of Tatneft, in Tehran for the signing, also visited Iran's giant South Pars gas field and said he hoped for further economic cooperation with Iran." (The Wall Street Jounal, "Russian company signs up to develop Iran oil field," 12/17/2011)