OPEC and Russia have defied the skeptics and their production cuts have eliminated half the oil-inventory surplus, meaning the rebalancing of the market is accelerating, said Secretary-General Mohammad Barkindo.

“A balanced oil market is now fully in sight,” Barkindo said at the Oil & Money conference in London on Thursday. “Stability is steadily returning and there is far more light at the end of the dark tunnel we have been traveling down for the past three years.”

The upbeat speech from the Organization of Petroleum Exporting Countries’ top official underscores the recent shift in market sentiment. The world’s two crude benchmarks are back in bull territory as thorough implementation of historic supply cuts by 24 OPEC and non-OPEC producers drained fuel stockpiles for several months. While the resurgence in U.S. shale still clouds the outlook for prices next year, oil exporters are feeling “a warmer glow,” Barkindo said.