Russia collected an estimated 21 billion euros ($21.7 billion) in fossil fuel exports last month, a seven percent drop from September, according to the Finland-based Centre for Research on Energy and Clean Air (CREA).
Revenue from exports to the European Union fell by 14 percent to 7.5 billion euros, below pre-war levels.
The EU will ban most imports of Russian crude oil next month. Refined oil products from Russia will be prohibited from February.
The 27-nation bloc has also placed an embargo on Russia coal. While it has not banned natural gas imports from Russia, Moscow has slashed supplies to the EU.
“A new route for Russian oil to the EU is emerging through Turkiye, a growing destination for Russian crude oil,” CREA said, referring to Turkey.
Ankara has increased imports of Russian crude since the Ukraine invasion started in late February, the think tank said.
The oil is then processed in Turkey, whose exports of refined oil products to the EU and the United States jumped by 85 percent in September-October compared to the July-August period, CREA said.
“Turkish refiners are therefore providing an outlet for Russia’s oil exports, by refining products for markets that are either not willing to import Russian crude oil directly or don’t have the refining capacity to process it,” it said.
“As the EU bans crude oil imports from Russia on 5 December, this loophole could become important,” CREA added.