method for quantifying uncertainties related to continuous and discrete parameters descriptive of a medium such as an underground zone and / or for managing the selection of a scenario from a series of possible scenarios relative to this medium , by construction of experiment designs and results analysis suited to the experiment designs constructed . the method essentially comprises constructing the factorial part of the experiment designs by folding a regular fraction for the quantitative factors and assignment of at least one modality of a qualitative factor to each one of the blocks formed by folding , determining the axial part of the qualitative factors according to a d - optimality criterion and analysing the results by combining a sensitivity analysis and a risk analysis involving marginal models and a global model . the method allows for example , in an otherwise uncertain context , to compare different production scenarios in order to better understand the role of non - controllable discrete parameters and / or to select the scenario which optimizes production in the case of controllable discrete parameters . application : reservoir exploration or engineering for example .