For reference the US consumed 7 billion barrels in 2015[1] so this represents basically nearly 3 years of consumption by the US with no imports at all. And world consumption has been nearly flat for a while.
That said, there is a lot of evidence and history that supports the notion that OPEC only managed to keep oil prices high by threatening member states with retaliation if they under cut the "standard" price. And at the same time, people who were in a position to undercut that price (Venezuela, Russia, Brazil) did so in order to get more foreign currency faster.
It is always a balance of incentives. The market clearly will buy oil at lower prices if given the opportunity.
So one could imagine an act of economic warfare where the oil and gas reserves were developed as quickly as possible and shipped to Europe at a steep discount to cut into the revenues Russia makes selling oil and gas. Thus putting a huge crimp in their economy which makes their military spending cut into their social programs more deeply causing internal unrest and dissatisfaction.
That certainly would not be in the best interests of the companies pulling the oil out of the ground, but it could be in the best interests of the US policy makers.
My original point was that the $900B number was specious, you cannot take the 'estimate of reserves in barrels' x 'the spot price of oil' and call it the 'value'. The quantity is material to the commodity price on the market and so moving it through the market will change the net value.