MOSCOW, Oct 11 (Reuters) - Russia's oil and gas revenue, which account for around a third of the federal budget, are set to rise to around 1.85 trillion roubles ($18.5 billion) in October, up 2.5 times from 0.74 trillion roubles in September, Reuters calculations showed on Wednesday.
The corresponding figure in October 2022 was 1.28 trillion roubles.
October figures will receive a boost of 0.68 trillion roubles from a profit-based tax on oil production in the third quarter, according to the calculations.
They will also benefit from a lack of "damping mechanism" subsidises paid to firms supplying the domestic market when fuel export prices are high.
The government paid refineries some 299 billion roubles in September under the damping mechanism, official data showed.
Reuters' calculations are based on data from industry sources and official statistics on oil and gas production, refining and supplies on domestic and international markets.
Proceeds from oil and gas sales are crucial for Russia's commodity-oriented economy and for the financing of what it calls its "special military operation" in Ukraine.
The finance ministry is due to publish its data on budget revenue from oil and gas in early November.
The ministry expects this revenue to decline by 23% to 8.94 trillion roubles this year, while the budget deficit is seen at almost 3 trillion roubles, or 2% of gross domestic product.