OPEC is probably the single most powerful organisation in the oil industry, able to influence the price of oil to help its member states; however a review by Bassam Fattouh and Lavan Mahadeva of the Oxford Institute for Energy Studies suggests that whilst OPEC is able to influence prices in the short term, it has less success over the long term.
While it is hard to ramp up much sympathy for petro-states, Norway and Saudi Arabia are both facing a murky 2013 as domestic production falls, pushing both nations towards some difficult (and expensive) choices.