Estimates I read from a 2004
National Energy Board paper on the Oil Sands estimated the total economicly recoverable deposits (which they listed as only only 11% of the total) at 28 billion cubic metres or approx 175 billion barrels of oil (one cubic metre = 6.3 barrels). They were using an average price of $24.00/Barel WTE for their economic calculations.
So... not sure about the 700 year figure, but certainly a lot of oil sitting there! And with any price over their figure of $24/barrel, more of the total deposit becomes economicly recoverable. With their figure of 175 billion barrels alone, there's approx $8,575,000,000,000.00 worth of oil at today's prices. Wow!