Mallard...good question.
Normally in a mature company, lets use GE, you would use the outstanding shares to value the worth of new revenue that is going to be generated. In the case of Oromin I think we need to use the market cap because of all the warrants that are outstanding. I have not dug into their financial reports but just from the tidbits I have picked up here and there I think their are several million warrants that are still outstanding and don't expire for quite sometime. That is one reason why you hear some on this board and at Stockhouse get so disgusted when Oromin issues more warrants b/c they are dilluting their shares.
Also to understand better how the projects will be valued google:
CIMVal Standards
It is a set of internation strds on how they use different value models to come up with the value of different explorations and their maturity.