Production, from dynamic data, of timely geological model of physical property characteristic of structure of underground layer being examined, includes parametrizing fine mesh model to obtain distribution of property

摘要

A fine mesh model is parameterized to obtain the distribution of the property. The scale is changed to find the property's distribution in a simulated model with a larger mesh, used to resolve fluid flow equations and obtain simulated dynamic data. Analytical relationships are determined connecting variations in the simulated data to corresponding variations in the parametrization factor The analytical relationships are obtained by combining derivatives of the simulated dynamic data relative to the parametrization factor to the scale of the simulation model and derivatives of the parametrization factor of the simulation relative to the parametrization factor of the fine geological model. The simulation model is calibrated to reduce errors introduced by the change in scale. This calibration stage involves: choosing a fine geological model a priori representative of the model studied (calibration model); directly determining the first simulation results compatible with this model; determining a simulation model by changing the scale of the fine geological model; directly determining second simulation results compatible with the formed simulation model, depending on the scale change parameters (c) and simulation parameters (s); and adjusting the calibration parameters (c, s) so the two sets of results are compatible. The physical property is the permeability or porosity of the rock. The dynamic data are production data such as pressure, the volumetric ratio of gas to oil (GOR) or the fraction of water in the oil. The parametrization parameter is selected by gradual deformation or pilot points. The scale change is done by a medium pressure analytical method, or a numerical method by resolution of a local or global flow problem.