A history matching method by gradual deformation of a fault network associated with a geological model is disclosed having application to notably petroleum reservoir development. A fault network is constructed by drawing fault centers in a multifractal density map constructed by a multiplicative cascading and by generating a fault for each fault center. History matching of the model is then performed by deforming the fault network through continuous deformation of the multifractal density map, then by reiterating the center drawing and fault generation stages.