"Risk" is the risk associated with the prospect of finding a volume of hydrocarbons that is within the volumetric range (e.g. 10-100 million barrels) specified for that particular prospect
"Unrisked" means the risk (as defined above) is not taken into account when calculating the potential net volume of hydrocarbons specified for the particular prospect.
But when given the risked number, one would think the unrisked would be a multiple of somekind?
Conditional estimates.-Sizes, numbers, or volumes of oil or natural gas that are estimated to exist in an area, assuming that they are present. Conditional estimates, therefore, do not incorporate the risk that the area may be devoid of oil or natural gas.
Risked (unconditional) estimates.-Resources that are estimated to exist, including the possibility that the area may be devoid of oil or natural gas. Statistically, the risked mean may be determined through multiplication of the mean of a conditional distribution by the related probability of occurrence. Resource estimates presented in this report are risked estimates.