The Organization of the Petroleum Exporting Countries, Russia and other non-OPEC producers on Nov. 30 extended an oil output-cutting deal until the end of 2018 to finish clearing a glut. But the market is interested in how producers will exit the deal once the excess is cleared.

"We are designing a framework for a continuity strategy for supply management to help ensure a stable and sustainable oil market," OPEC Secretary General Mohammad Barkindo said in a speech in China.

Any exit strategy would be gradual, Kuwait's oil minister said earlier on Wednesday.