Patent Document ID: 7496488
Application ID: 10997539
Patent Status: 1

Claim One:
1. A multi-scale computer implemented method for use in modeling a subsurface reservoir comprising: (a) creating a fine grid defining a plurality of fine cells and having a permeability field associated with the fine cells; (b) creating a coarse grid defining a plurality of coarse cells having interfaces between the coarse cells, the coarse cells being aggregates of the fine cells; (c) creating a dual coarse grid defining a plurality of dual coarse control volumes, the dual coarse control volumes being aggregates of the fine cells and having boundaries bounding the dual coarse control volumes; (d) calculating dual basis functions on the dual coarse control volumes by solving local elliptic or parabolic problems; (e) extracting fluxes across the interfaces of the coarse cells from the dual basis functions; (f) assembling the fluxes to calculate effective transmissibilities between coarse cells; (g) calculating pressure in the coarse cells using a finite volume method and utilizing the effective transmissibilities between coarse cells; and (h) computing a fine-scale velocity field responsive to the calculated pressure in the coarse cells for use as a variable in modeling fluid flow in the subsurface reservoir with a subsurface reservoir simulator, the fine-scale velocity field being computed directly in place and including the steps: (i) computing fine-scale fluxes across the coarse cell interfaces using the dual basis functions with the calculated pressures in the coarse cells; (ii) solving a pressure equation on each of the coarse cells using the fine-scale fluxes computed in step (i) as boundary conditions to obtain fine-scale pressures; and (iii) computing the fine-scale velocity field from Darcy's law using the fine-scale pressures obtained in step (ii).