Producers from the Organization of the Petroleum Exporting Countries (OPEC) and non-OPEC players including Russia have agreed to cut output by 1.8 million barrels per day (bpd) until the end of 2018 aiming to support prices and reduce inventories.

"The extension of the OPEC+ deal beyond 2018 would mute Rosneft large-scale greenfield prospects, and postpone their launch and ramp-up," Moscow-based Aton said.

Rosneft has said it could delay the start of production at some new fields, namely east Siberia's Uyrubcheno-Tokhomskoye and Russkoye in the northern Yamal Nenets region.

Rosneft boss Igor Sechin, a close ally of Russian President Vladimir Putin, has expressed scepticism about the effectiveness of the output reduction pact given that US shale producers, who are not participating, continue to ramp up production.

Aton also said Rosneft could raise output by 100,000 barrels per day in around three months once the pact ends.