Method of generating a conforming hybrid grid in three dimensions of a heterogeneous formation crossed by one or more geometric discontinuities in order to carry out simulations

摘要

Method of generating a hybrid grid, in order to carry out simulations in accordance with a defined numerical scheme, in three dimensions and admissible in the numerical scheme sense, of a heterogeneous formation crossed by one or more geometric discontinuities such as, for example, an underground formation where one or more wells have been drilled, or a fractured formation, by combining structured grids and unstructured grids. The hybrid grid is achieved by associating a first structured grid for gridding the heterogeneous medium with second structured grids for gridding a zone around each discontinuity. A cavity of minimum size, allowing the cells of the transition grid to have an intermediate size between the size of the cells of the first grid and the size of the cells of the second grids, is first generated, entirely automatically. A transition grid meeting the constraints of the numerical scheme used for simulation is then constructed. Finally, the quality of the transition grid is improved by optimizing it under quality controls in the numerical scheme sense, in order to define a perfectly admissible transition grid in the sense of the numerical scheme selected. Applications: hydrocarbon reservoir simulators for example.