An Iran nuclear deal could mean bad news for the Russian oil business. The most obvious source of pain is that the introduction of Iranian oil on the market after sanctions are lifted could push oil prices down again. But that's not the only sore spot. In the last few years, Russia encroached on Iran's primary markets, Asia and Europe, and that trend could reverse following the deal. “Iran is going to be competing in Europe head-on with Russia,” Ed Morse, head of commodities research at Citigroup Inc. previously told Bloomberg. Before the Western sanctions, Iran's crude exports "were a regular fixture for European refineries." But since 2012, Iran has been banned from selling oil to Europe, and additional US sanctions made it harder to buy Iranian oil with US dollars. So, "Russia, whose benchmark export grade is similar to Iran’s flagship blend, has been the main beneficiary of that decline," Bloomberg reported recently. "Exports into Iran’s main markets in Asia and Europe have more than doubled, growing by 420,000 barrels a day from 2011 to 2014." Citi's Edward L. Morse included a chart (to the right) in a June 30, 2015 report to clients, showing Iranian crude exports by destination, where the loss of the European market is clear. However, things could be change up now: many Mediterranean refiners are ready and excited for the return of Iranian oil. "Iran has been a long standing valued partner ... We are looking forward to Iran coming back to the market," a spokesman for Greece's biggest refiner Hellenic Petroleum told Reuters. "The volumes of crude oil that will re-enter the Mediterranean market will ease prices and give more options for refiners in the region," he added. He stated, however, that they will not buy any crude before sanctions are officially lifted. Additionally, a spokeswoman for Spain's Compania Espanola de Petroleos (CEPSA) reportedly said that "Iranian crude has largely been part of our supply and we maintained a long commercial relationship with them." "If sanctions are lifted, as it seems, Iranian crudes will definitively be again another alternative to consider," she added in a statement to Reuters. Analysts expect the deal could see Iran increase its oil exports by up to 60 percent within a year, according to Reuters. "It would mean cheaper crude for Mediterranean refineries, especially smaller countries that have been impacted by economic problems – like Greece," Eshan Ul-Haq said, a senior market consultant with KBC told Reuters.SEE ALSO: This map shows what $100 is actually worth in your state Join the conversation about this story » NOW WATCH: 6 compelling correlations that make absolutely no sense