"Iran is sitting on an estimated 836 billion barrels of oil and condensates in place, of which 239 billion barrels are recoverable," said Karim Zeibodi, head of a special department at NIOC that oversees performance of reservoirs, Mehr News Agency reported on Sunday.
Iran holds a total of 711 billion barrels of oil with a recovery factor of nearly 25%, or about 175 billion barrels.
Recovery factor is the ratio of technically and economically recoverable reserves to the total amount of oil in a reservoir.
"Data shows that 1% increase in recovery rate will translate into 7 billion barrels of crude oil. This will bring in more than $280 billion in revenues with oil priced at $40 per barrel," Zeibodi noted.
Recovery factor at Iranian oilfields ranges between a low of 5% and 60%.
According to Oil Minister Bijan Namdar Zanganeh, Tehran has prioritized the development of joint fields and boosting the extraction rate from operational fields.
Iran is also home to the second largest gas reserves in the world after Russia.
Iran (34 trillion cubic meters) and Russia (32.6 tcm) hold the largest proven gas reserves, according to BP Statistical Review of World Energy 2015. But the US Energy Information Association places Russia ahead of Iran with an estimated 49 tcm.
Iran, Russia and Qatar together hold nearly half the world's proven gas reserves.
Currently the third largest producer in the Organization of Petroleum Exporting Countries, Iran is planning to develop its key oil and gas projects under a new model of contracts, dubbed Iran Petroleum Contract, that offers multinationals better terms and conditions for investment, according to Financial Tribune.
Oil, Gas Reservoirs
According to Zeibodi, Iran has 358 oil and gas reservoirs, including 195 undeveloped fields.
"We need to implement enhanced recovery techniques to raise output from more than 68% of our reservoirs," he added.
According to government data, Iran’s in-place oil in the Persian Gulf amounts to 100 billion barrels, some 16 billion barrels of which are recoverable.
Officials said in March that Iran's in-place oil reserves had increased by 2.5 billion barrels, using enhanced oil recovery techniques such as gas injection that maintains reservoir pressure and improves oil displacement.
Iran is seeking modern technology to boost oil and gas extraction. Lloyd’s Register, an international technical and business services firm based in London, held an exclusive one-day event in Tehran in July to brief Iranian companies on the latest developments in the EOR sector.
China National Petroleum Corporation has also signed an agreement to boost production in Masjed Soleyman Oilfield—the Middle East's oldest oilfield—via advanced EOR methods.