Price of oil per barrel used to float in an average discrepancy of between +/-3 USD/bbl compared to WTI and OPEC Basket. But this changed after September of 2010 when the crude oil price gap grew significantly compared to WTI, reaching over $11 a barrel by end February 2011 (WTI: 104 USD/bbl, LCO: 116 USD/bbl). Some blame the depletion of oil fields under the North Sea. But the cause of this oil price evolution may be linked as well to currency fluctuations, varying demands on the regional market, possibly politics? Historically, similar price of oil spreads are an effect of short term physical variations in supply and demand.