1. A method for updating a geological reservoir model representative of the behavior of a heterogeneous porous medium and discretized in space into a set of cells forming a grid representative of structure of the medium, allowing accounting for dynamic data acquired by measurements and varying in time according to fluid flows in the medium, the method comprising: A) constructing an initial map of petrophysical properties by means of a geostatistical simulator and of static data; and B) integrating the dynamic data (DD) by optimizing the initial map by carrying out: a) constructing an initial set of gradual pilot points; b) constructing at least one complementary set of gradual pilot points; c) constructing a combined set of gradual pilot points by combining the sets of gradual pilot points according to a gradual deformation method wherein at least one deformation parameter is a characteristic parameter of the pilot points; d) modifying values of petrophysical properties of the initial map by constraint by the combined set of gradual pilot points and by the static data; e) modifying the combined set and resuming from c) until a stop criterion is reached; and C) updating the geological reservoir model by associating the map optimized in B) with the grid of the model.