The increasing growth in demand for crude oil from economies such as China, India and the Middle-East has had an impact on the prices of oil, which reached a record level of $145 per barrel in 2008. Changes in the price of oil are increasingly significant and have influenced every economy around the world. The analysis of oil prices has always been of considerable interest to all people. Established in September 1960, the Organization of Petroleum Exporting Countries (OPEC) exercises enormous influence on the world prices of oil due to many factors, particularly its spare oil capacity of roughly 4 million barrels per day in 2014, based on an assumed 85% utilization rate.1 Additionally, according to the International Energy Agency (IEA), non-OPEC countries had an excess demand of 35.5 million barrels per day in 20132 ; this gap is satisfied with the oil supplied by the 12 members of OPEC.3 In 2013, the non-OPEC share of global oil production was approximately 59.8% of the total world production of oil. Due to the nonOPEC excess demand-supply, it is a common belief that non-OPEC producers behave as price takers and that OPEC may play a central role in the world oil market by adjusting its production and setting the prices of oil. However, it remains the case that the dynamics in crude oil markets depend on their different market fundamental situations [2,3]. These dynamics are attributed to their price regimes such as Brent, West Texas Intermediate and OPEC Reference Basket. The oil market itself appears to be in charge of pricing. There is a vast literature on the price of oil. Gately [4] establishes that the reductions in the world demand for oil following the increase in oil prices in the 1970 s have not been completely reversed by the price cuts of the 1980 s. De Santis [5] explains the volatility of crude oil prices by focusing on the quota regime as a primary characteristic adopted by OPEC agreements. Recently, Nakov and Nuño [6] incorporated the ample spare capacity and the volatile domestic production, as features of Saudi Arabia, into a general equilibrium model where the global oil market is modeled as a dominant producer with a competitive fringe. They find that Saudi Arabia produces a smaller amount of oil than its capacity given the oil price, allowing it to charge a markup over its marginal cost. Lin [7] finds oligopolistic behavior among non-OPEC producers and collusion among OPEC producers during the period 1970– ۲۰۰۴٫ Hamilton [8] investigates the factors responsible for changes in crude oil prices by reviewing the statistical behavior of oil prices and the key features of crude oil supply and demand.