Fact box 3.3 Prospects and leads

A prospect is a possible petroleum deposit where no drilling has taken place but which has been mapped and a volume calculated.

The estimated likelihood of proving oil and/or gas in a given prospect is called the probability of success.

A lead is a possible petroleum trap where available data coverage and quality are inadequate for mapping or delimiting the rock volume.

A postulated prospect (figure 3.9) is one which could be mapped in the future (but not identified at the moment because, for example, the data are inadequate).