Patent ID: 7200533

Claim:
A method for speeding up forming a stochastic numerical model of a Gaussian type or a type representative of a distribution of a physical quantity in a porous heterogeneous medium, calibrated in relation to dynamic data obtained by measurements performed in the medium or by previous observations, and a characteristic of displacement of fluids therein, comprising an iterative process of gradual deformation wherein an initial realization of at least part of the medium is linearly combined, upon each iteration, with at least a second realization independent of the initial realization, coefficients of the linear combining being such that a sum of the squares of the coefficients is 1, and an objective function measuring a difference between a set of non-linear data deduced from the linear combining by means of a flow simulator and the dynamic data are minimized by adjusting the coefficients of the linear combining, the iterative process being repeated until an optimum realization of the stochastic model is obtained in which a rate of deformation to an optimum model representative of the medium is accelerated by selecting as the second realization to be combined with the initial realization at least one composite realization obtained by selecting beforehand a direction of descent defined as a function of gradients of an objective function in relation to all the components of the initial realization.