The last change was in June, when OPEC and 10 non-OPEC countries agreed to return to 100 percent compliance with supply cuts that had been overdelivered on, amounting to a production increase of 1 million barrels per day.

Six months on, producers are heading for a policy U-turn after a 30 percent slide in prices since October on concerns about oversupply. OPEC and its allies including Russia meet on Thursday and Friday in Vienna to discuss cutting output again.