There's also plenty of gold dissolved in the rock of the mantle and at the center of the core. "Wood calculated that 1.6 quadrillion tons of gold must lie in Earth's core." That's 10*15 tons assuming he's using the modern numbering system.
http://discovermagazine.com/2006/sep/innerfortknox

Vs. 6000 billion barrels of oil in place, which is 6x10*15
http://www.eia.doe.gov/pub/oil_gas/petroleum/feature_articles/2004/worldoilsupply/oilsupply04.html

So they're actually not that far off from each other--within the error of these estimates at least. I'm surprised...