The Western sanctions have left Gazprom largely unaffected, including with respect to the execution and extension of existing contracts and the conclusion of new contracts for gas supplies with foreign parties, and have had little bearing on the Company's ongoing activities.

Gazprom's Deputy Chief Executive Alexander Medvedev said the BG holdings could be included in an asset swap deal between Gazprom and Shell that was announced last year. He did not say what the BG holdings were or where they were located.

“The US has sought to work with Europe to lessen Europe's dependence on Russian energy and, particularly, gas supplies to weaken Russian leverage to use that gas supply for political purposes and has enjoyed some success, and this has been a cooperative venture. Three administrations working in the same direction, many of the same assumptions and people.”

In addition to Vietnam, Rosneft also has oil-producing assets in Venezuela and Canada. It has exploration prospects in several other countries, including in Mozambique and the US in partnership with ExxonMobil.

While Iran enjoys the world's fourth-largest proven crude oil reserves and the world's second-largest natural gas reserves, its production and export potential has remained largely unutilized as a result of the nuclear related sanctions. The sanctions have had a major impact on Iran's energy industry and have caused a number of cancellations or delays in its oil and gas upstream projects.

Rosneft received advance payments for oil supplies worth more than $15bn in the third quarter — the first large-scale financing that the state-controlled Russian group has secured since western sanctions were imposed upon it.

The U.S. declared one of Russia’s largest offshore oil and natural gas fields off limits to American tools and expertise, potentially disrupting Royal Dutch Shell Plc’s plans to liquefy the fossil fuel for export.

In the medium term, Iran’s gas will not be able to compete with the Russian gas in the European market.

Seven months after Russia made the latest changes to its oil tax regime, the industry seems to have been able to adapt more easily to the new landscape than had been expected at the turn of the year. However, market experts have warned that the government must consider more fiscal reforms as the current system is continuing to distort the sector. The so-called tax maneuver, which includes a phased reduction in export duty for crude and oil products over 2015-2017 and an increase in oil extraction tax, was introduced in January.

Gazprom's gas prices are pegged to oil with a six-month lag, which means its customers are currently paying the equivalent of $45-$50 per barrel seen in January 2015 when oil prices crashed following a decision by OPEC not to reduce output.