Method for determining uncertainties associated with a model of a sedimentary basin

A method for determining uncertainties relative to at least one physical property of a sedimentary basin using a numerical simulation which is a computer-implemented stratigraphic simulation or basin simulation, carried out with simulation parameters comprising steps of:

• A) measuring with sensors physical quantities relative to the basin and determining at least values of the simulation parameters;
• B) selecting uncertain simulation parameters and defining combinations of possible values of the uncertain simulation parameters;
• C) determining grid representations of the basin using cells by using the numerical simulation, each of the grid representations being obtained for one of the combinations of possible values of the uncertain parameters, each of the cells of the grid representations comprising at least one value allowing the at least one physical property to be determined,
• wherein, for at least one of the physical properties of the sedimentary basin, performing at least steps of:
• D) for each of the grid representations determining a realization of a spatial distribution of the at least one physical property, applying a principal component analysis to the realization of the spatial distribution of the at least one physical property, selecting principal components having a sum of associated eigenvalues greater than a predefined threshold, and determining an analytical model of the spatial distribution of the at least one physical property by constructing an analytical model for each of the selected principal components;
• E) constructing, as long as a stopping criterion is not satisfied, an analytical model of the spatial distribution of the at least one physical property iteratively with improved accuracy by determining for each iteration, at least one additional combination of possible values of the uncertain parameters by using an adaptive sequential planning method applied to the analytical models of the selected principal components, by considering the selected principal components in a descending order of their eigenvalues until an accuracy indicator relative to at least the selected principal component of a current iteration is reached, and by repeating steps C) to E);
• and
• F) from the analytical model with improved accuracy of the spatial distribution of the at least one physical property, uncertainties relative to the spatial distribution of the at least one physical property of the sedimentary basin model are determined.