Abstract: A method for gradually modifying a geological model representative of an underground reservoir to respect fixed average proportions of lithologic facies. A group of facies is selected and a subgroup of associated facies are selected. A transformation parameter is defined by the ratio between the average proportions of the facies of the association and the selection. Within the context of historical matching, a difference between measured dynamic data values and values calculated by a flow simulator from the geological model is measured. An optimization algorithm is used to obtain therefrom a new value for the transformation parameter that minimizes the difference and the transformation is applied to the lithologic facies of the selection. The modification can be applied to the entire model or to a given zone.

Abstract: Method for gradually modifying a geological model representative of an underground reservoir so as to respect fixed average proportions of these lithologic facies. A group of facies referred to as selection and a subgroup of facies referred to as association are selected. A transformation parameter is defined by the ratio between the average proportions of the facies of the association and those of the selection. Within the context of history matching, a difference between measured dynamic data values and values calculated by means of a flow simulator from the geological model is measured. An optimization algorithm is used to deduce therefrom a new value for the transformation parameter that minimizes this difference and this transformation is applied to the lithologic facies of the selection. The modification can be applied to the entire model or to a given zone.