Method for forming an optimum stochastic model of a heterogeneous underground zone, calibrated with dynamic data by parametrization of continuous distributions

摘要

Method for forming an optimum stochastic model representative of the spatial distribution, in a heterogeneous underground zone, of physical quantities such as permeability and porosity, constrained by measured dynamic data, representative of fluid displacements in the medium, using a continuous distribution parametrization technique. The model is calibrated with the dynamic data by means of an iterative process of minimization of an objective function measuring, on each iteration, the difference between the dynamic data measured and dynamic data simulated by means of a flow simulator, obtained from a realization interpolated between a reference realization (initial or obtained at the end of the previous iteration) and another independent realization, by adjustment of a perturbation parameter, the iterative adjustment process being continued until an optimum realization of the stochastic model is obtained. The method applies in particular to Gaussian sequential simulations and, in particular, to Gaussian white noises, from which any type of stochastic models (continuous, facies or object models, etc.) can be constructed. Application: elaboration of an underground reservoir model allowing to simulate the configuration of various heterogeneities: permeability, porosity, fractures, channels, etc.