國際油價點定？OPEC or market?

There are 3 factors mainly affecting the Price of oil.

The first one,,as u say ,market demand and supply!! When the economy goes well,,especially manufacturing doing good,,demand raise up...price follows. And suppliers decide the supply amount,,supply decrease, price also goes up.

The second one is investor,,trading commodities to gain profit.

The third one is about USD rate, USD goes up, oil price decline,, otherwise, it increase..