The no campaign argues that dependence on oil money would leave Scotland dangerously exposed to fluctuations in its price.
How much oil is left?
The Scottish government offers the more optimistic estimates, and suggests that the boost it would give to an independent Scotland's GDP offers the opportunity to build the social democratic state that it says the majority of Scottish voters seek.
Last week Scottish ministers seized on a report suggesting that fracking in the North Sea could propel an independent Scotland towards the top of the global league table in oil and gas production. It was claimed that fracking could amost double the amount of recoverable oil and gas in the North Sea. Others suggest this is wishful thinking.