Major oil producers have seen enough success to stick with their current strategy . Where previous meetings of OPEC and non-OPEC nations were surrounded by uncertainty, all signs suggested that the recent meeting in Vienna would lead to an extension of the current deal cutting oil production. That extension would leave two major questions: How long would the extension run and would an exit strategy be put in place. On Nov. 30, OPEC and non-OPEC producers agreed to extend the deal until the end of 2018, with a review of the duration scheduled for June. The deal will continue, but the strategy for how and when it will end remains murky. Thus far, the agreement to cut output has served its purpose . Brent crude oil — a major benchmark for global oil prices — hovered around $63 a barrel for most of November.