The oil prices will decrease sharply in the long run mainly because______.

The head of one of the world’s biggest oil companies has predicted that oil prices will stay at their current high level in the near future, but are likely to drop sharply in the long term. John Brown, chief executive of the British firm BP, said in an interview with a German news magazine that the price of oil could halve in the next five years. He added that larger reserves still remain undiscovered or untapped and that new technology would bring down extraction costs.