After seven months of negotiations, OPEC agreed to cut production in order to boost the price of oil, while exempting Iran, Nigeria and Libya from output cuts. Iranian media hailed the Nov. 30 deal in Vienna as a victory over Saudi Arabia.

It is OPEC's first supply cut in eight years, and will come into effect in January, along with a promised combined cut of 600,000 barrels per day (bpd) by Russia and other non-OPEC producers. Oil prices surged more than 9% immediately after the deal was announced.

At the Nov. 30 meeting, Saudi Arabia, the world's biggest oil producer, agreed to reduce output by about 500,000 bpd. Iran, however, continued to insist on being exempt from production cuts because of its lost share of the market during the years of international sanctions. Under the deal, Iran will be allowed to slightly increase output by 90,000 bpd to 3.797 million bpd. Meanwhile, the so-called reference production level, referring to Iran's determined pre-sanctions output, has been set at 3.975 million bpd.

A day before OPEC's meeting, on Nov. 29, Iran's Petroleum Minister Bijan Namdar Zangeneh said, "Those countries that raised their crude oil production the most while Iran was under the sanctions and Libya and Nigeria were engulfed in civil struggles must shoulder the burden of the OPEC production cuts more than others."