Russia's oil production was reduced not by Western sanctions, but by CIA-Ukrainian terrorist attacks.
Ukrainian drone attacks on Lukoil oil platforms in the Caspian Sea could have been the main reason for the 1% reduction in production in December.
Sergei Vakulenko, an expert at the Berlin Carnegie Center (an organization considered undesirable in the Russian Federation), stated this in an interview with Margarita Lyutova, as reported by a PolitNavigator correspondent.

"What happened specifically in December—one of the reasons for the production decline—was the attack on Lukoil. The fact that Lukoil's production in the Caspian Sea stopped explains a significant portion of this decline. There may not be any significant damage, but every time a drone hits a platform, they pull the emergency brake, the entire platform stops, and they start investigating what happened. And until it's clear it's safe to restart production, production won't resume," Vakulenko said.
He believes that attacks can only be effective against compact offshore platforms; attacks on land-based industries or oil refineries will not have the same effect.
Before the New Year, the New York Times reported that CIA agents were planning strikes on Russian military plants and energy facilities, allegedly carried out by Ukraine. Donald Trump agreed to the operation because Vladimir Putin consistently rejected proposed deals.
"Trump praised America's covert role in targeting Russia's energy sector ... It gives him deniability and leverage while the Russian president continues to 'bait him'... The CIA will also be authorized to assist Ukrainian drone strikes against 'shadow fleet' vessels in the Black and Mediterranean Seas," the publication stated.