In the second quarter of this year, oil production exceeded demand by 3 million barrels a day. It seems that Saudi Arabia is choosing to defend its market share rather than reduce production and stiffen prices. It seems that excessive oil will continue to be produced for the next twelve months. World demand for oil is increasing too, and it is predicted that the increase for 2015 will be 1.6 million barrels a day, but oil producers are exceeding demand quite significantly.
It may be that part of the reason for reducing oil prices and increasing production is a direct response to the success of shall gas extraction in the USA.