Algerian Prime Minister Abdelmalek Sellal (C) poses with oil ministers from OPEC member states and other officials attending the opening session of the 15th International Energy Forum in Algiers on September 27, 2016.(AFP Photo)

ALGIERS, Sept. 27 (Xinhua) -- Representatives from over 50 countries and 82 energy companies started here on Tuesday an international forum that is expected to discuss stabilizing a volatile oil market and developing green energy.

The theme of 15th annual International Energy Forum (IEF 15) is "global energy transition: an enhanced role for energy dialogue."

Four closed-door sessions are scheduled for Tuesday on the oil market, the liquefied gas market, renewable energies, and energy governance.

The informal meeting of the Organization of Petroleum Exporting Countries (OPEC) will be held on the sidelines of the IEF 15.

"I'm very optimistic that OPEC members would reach a consensual agreement to restore stability to the up-and-down oil market," Algerian Energy Minister Noureddine Bouterfa told a press conference preceding the informal meeting of the OPEC in Algiers.