S4  Ciências e Engenharia do Petróleo    Titulo: MINIMIZATION OF GRID ORIENTATION EFFECTS BY USING ENO AND TVD SCHEMES IN RESERVOIR SIMULATION USING NON-ORTHOGONAL BOUNDARY-FITTED COORDINATES   Resumo : THE SOLUTION OF THE DISPLACEMENT FRONT IS ONE OF THE TOUGHEST PROBLEMS IN RESERVOIR SIMULATION, SINCE ITS ACCURACY DEPENDS STRONGLY ON THE APPROXIMATION SCHEME USED FOR THE CONVECTIVE TERMS OF THE GOVERNING EQUATIONS. THE SCHEME NORMALLY USED IS THE UDS (UPSTREAM DIFFERENCING SCHEME) THAT STABILIZES THE NUMERICAL SOLUTION, BUT INTRODUCES HIGH LEVELS OF NUMERICAL DIFFUSION. THE NUMERICAL DIFFUSION PROVOKES TWO IMPORTANT MANIFESTATIONS. ONE IS THE SMEARING OF THE FRONT, WHICH CAN CAUSE WRONG FORECASTS OF THE BREAKTHROUGH. THE OTHER ONE IS THE DISTORTION OF THE DISPLACEMENT FRONT, THE WELL-KNOWN GRID ORIENTATION EFFECT. HIGH-RESOLUTION METHODS, LIKE TVD (TOTAL VARIATION DIMINISHING) AND ENO (ESSENTIALLY NON-OSCILLATORY), ARE ABLE TO REDUCE THE NUMERICAL DIFFUSION. SPECIALIZED LITERATURE IN RESERVOIR SIMULATION SHOWS HOW TO IMPLEMENT TVD SCHEMES IN A CARTESIAN AND BOUNDARY-FITTED COORDINATES. ON THE OTHER HAND, ENO SCHEME WAS INTRODUCED IN RESERVOIR SIMULATION ONLY FOR CARTESIAN GRIDS. THIS PAPER SUGGESTS AN ENO SCHEME TO BE USED IN RESERVOIR SIMULATION WITH BOUNDARY-FITTED COORDINATES. THE PERFORMANCE OF NUMERICAL METHODS, LIKE UDS, TVD AND ENO, IS ANALYZED FOR A RESERVOIR ENGINEERING PROBLEM AND COMPARISONS ARE MADE WITH A REFINED GRID UDS SOLUTION.    Autores : Czesnat, Alexandre de Oliveira Lucianetti, Rodrigo Machado Maliska, Clovis Raimundo     Trabalho Completo :   COBEM99 | Comissão  Organizadora | Palestras | Sessões Técnicas | Autor | Simpósios e Sessões Especiais | Revisores |  Título  dos  Trabalhos | Local