Navigation:  Prospect/Field evaluation > Input parameters > Prospect Risking > Prospect Risking Schemes > Prospect Risking - Scheme 8

In this scheme, overall Prospect Chance is divided into Play Chance and Prospect Specific Chance.

Play Chance is divided into three categories: Reservoir, Seal and Source (or Regional Reservoir, Regional Seal and Regional Source).

Prospect Chance is divided into four categories: Trap, Seal, Reservoir and Hydrocarbon Charge.

Each category has two or more key elements. You are required to assign a chance to each element. The category chance is the lowest of all the element chances (a "minimum risking" scheme).

Individual chances are rounded to the nearest 5%.

For example, Reservoir Chance has two elements: 'presence' and 'effectiveness'. If you assign 'presence' a chance of 80% and 'effectiveness' a chance of 60% then 'effectiveness' is the determining element and the Reservoir Chance is 60%.

The overall Prospect Chance is the multiplication of the Play Chance and Prospect Specific Chance:

Overall Prospect Chance = P100 = P(play) x P(prospect specific)

P(play) = P(regional reservoir) x P(regional seal) x P(regional source)

P(prospect specific) = P(trap) x P(seal) x P(reservoir) x P(charge)