Oil prices rose on Friday after Russia’s deputy prime minister, Alexander Novak, said that his country would cut production in March by 500,000 barrels a day — or about 5 percent of its output.Russia is the world’s third-largest producer of oil, and the announcement by Mr. Novak, who is the Kremlin’s point person on energy, immediately sent prices more than 3 percent higher before they eased. Later in the day, futures for Brent crude, the international benchmark, were 1.6 percent higher, at $85.61 a barrel. West Texas Intermediate rose similarly, briefly rising above $80 a barrel.The cutback in production would be Moscow’s first substantive response to a wave of recently imposed sanctions on Russ …