OPEC faces a new set of questions after winning output cuts from non-members and members of the oil cartel in recent weeks.
Analysts say the potential upside for the deal shouldn't be played down: Non-OPEC members on Saturday committed to reducing output by 558,000 barrels a day. If implemented, that would amplify the effects of 1.2 million barrels worth of daily cuts from OPEC for the first half of 2017.
But now market watchers are shifting their focus to other questions: Will the producers stick to their promises? Can they keep prices in a narrow range? How much will high-cost U.S. production rise as prices bounce?