| A three-dimensional compositional chemical flooding simulator (UTCHEM) has been improved to extend its applicability to field-scale simulations. The new mathematical formulation, boundary conditions, and a description of the physicochemical models of the simulator are presented.;This improved simulator has been used for the study of the low tension pilot project at the Big Muddy field near Casper, Wyoming. Both the tracer injection conducted prior to the injection of the chemical slug, and the chemical flooding stages of the pilot project, have been analyzed. This is the first published work where, using a compositional simulator, not only the oil recovery but also the tracers, polymer, alcohol and chloride histories have been successfully matched with field results.;Simulation results indicate that, for this fresh water reservoir, the salinity gradient during the preflush and the resulting calcium pickup by the surfactant slug played a major role in the success of the project. In addition, analysis of the effects of the crossflow on the performance of the pilot project indicates that, for the well spacing of the pilot, crossflow does not play as important a role as it might for a large-scale project.;To improve the numerical efficiency of the simulator, a third order convective differencing scheme has been applied to the simulator. This new method has been compared with several alternative methods commonly used to discretize the convection term of the mass conservation equations of compositional simulators. This higher order method can be used at higher cell Peclet numbers, resulting in a substantial saving in computation time for the same level of accuracy. Furthermore, this method can be used with non-uniform mesh, and therefore is suited for simulation studies of large-scale, multiwell, heterogeneous reservoirs.;Comparison of the results with one and two dimensional analytical solutions shows that this method is effective in eliminating numerical dispersion using relatively large grid blocks. Results of one, two and three-dimensional miscible water/tracer flow, water flooding, polymer flooding, and micellar-polymer flooding test problems, and results of grid orientation studies, are presented. |
