New Delhi: State-owned explorer ONGC Videsh is scouting for new global assets as the prospects of developing the Farzad B gasfield in Iran, estimated to hold 18.75 trillion cubic feet (tcf) of in-place reserves, appear to be slipping away.

"We had hoped that Farzad would add to our output target and have been extremely flexible in dealing with Tehran. So far, the deal is not finalised... (we) are looking for some producing assets elsewhere," ONGC Videsh managing director N.K. Verma said.

The company is looking at assets in Africa, Central Asia and Latin America.

Iran has been playing tough in its negotiations despite New Delhi expecting a favourable response, having helped the country during the years of economic sanction.

Sources said the OVL-led consortium revised its development plan to $11 billion to include downstream activities and linked the gas prices to the international benchmark.

However, Tehran is not satisfied with the revised plan and has asked OVL to commit itself to buy gas at a higher rate and operate the field for two decades, they said.

"The condition imposed by Iran is not acceptable as the return on investment would be in single digits and does not justify investment and production risk," Verma said.

However, oil ministry officials said "these are part of the negotiation strategy... each side wants to extract the maximum benefit".

The official said the main concern of the Indian side regarding the Farzad B field was the quality of gas and whether it was worth the investment.

"The internal rate of return (IRR) requirements have to be met. It has to be recognised that Farzad B is the most difficult field because of the sour gas, and other considerations such as the impurities," the official added.

ONGC Videsh is targeting production of 60 million tonnes of oil and gas by 2030 from 12.80 million tonnes in 2016-17.

The consortium had spent $900 million in the Farzad-B field to study the block following a 2002 preliminary pact with the Iranian authorities. The two sides have not signed any formal contract to exploit the resources till date because of the US sanctions.

The consortium, which also includes Oil India and Indian Oil Corp, could not move ahead to develop the field because of Western sanctions against Iran's nuclear programme. However, as those sanctions have been lifted earlier this year, efforts are on to formalise a deal to develop the field.

The consortium had discovered gas reserves in the Farsi block in 2008. OVL and IOC hold 40 per cent interest each in the block, while the remaining 20 per cent is with Oil India.

The deal with Iran would provide a great boost to the Modi government, which has been focusing on global assets for energy security.

The aim is to increase the share of gas in the country's energy basket to 15 per cent from 6.5 per cent. The country's share of gas in the energy basket is poor compared with the global average of 24 per cent.

According to the Vision 2030 report of the oil ministry, the natural gas demand is forecast to be more than 516.97 million cubic metres per day in 2021-22.