The Opec summit show is over and the performers have left town. But the preparations for Act Two, the meeting of oil ministers in Abu Dhabi on December 5, are already under way.

The scene is being set for a contest over whether to accept an oil price close to $100 a barrel or try to bring it down by raising production, with Iran and Venezuela on one side and Saudi Arabia on the other. The ministers’ decision will be an important signal of whether the influence of Saudi Arabia, traditionally the group’s most powerful member, is on the wane.