The run-up in gas prices has many factors, but it was intensified by Russia’s invasion of Ukraine and subsequent Western sanctions on the Kremlin, which disrupted supply from what had been the world’s third-largest oil producer. Russian output has fallen by more than 1 million barrels per day due to export sanctions that complicate sales and import sanctions that hurt production, according to Rory Johnston, an analyst at Commodity Context. Refineries necessary to turn oil into gas and other products are stretched to their limits, with Russian refineries knocked offline and U.S. refining capacity down roughly 5 percent, according to the Energy Information Administration.