Probability of success is established by considering both geological and commercial factors.

The probability of geological success includes the four main geological components needed to have a petroleum system for commercial production and include: (1) presence of source rock available which is capable to generate hydrocarbons; (2) presence of adequate quality reservoir rock and better than cutoff parameters values to accumulate the hydrocarbons in; (3) a stratigraphic or structural trapping mechanism with a seal with retention capability of top sealing unit to hold the hydrocarbons (4 way closure; fault closure; hydrocarbon retention capability / lateral seal); and (4) a mechanism and proper geological timing allowing for hydrocarbons to migrate into the trap (trap formation/timing, hydrocarbon generation timing, hydrocarbon expulsion timing, route and distance of migration pathway.

Geological chance of success entails the presence of 6 parameters:

Chance of source rock being present (x%) and of source rock being effective (x%)
Chance of reservoir being present (x%) and of reservoir being effective (x%)
Chance of cap rock being present (x%) and of cap rock being effective (X%)

or Trap integrity, Reservoir integrity, Source evaluation, Timing/Migration