| In this study a new multi-purpose numerical model for petroleum reservoirs has been developed. The model is capable of simulating black-oil reservoirs as well as secondary and some tertiary recovery processes. The simulator models the isothermal flow of oil, water, and gas in porous media in two dimensions and either in rectangular or cylindrical-radial coordinates.;A fully implicit well formulation was used and well block pressure was solved simultaneously. Multiple wells can be specified with variable injection and production schemes. In the case of rectangular coordinates, an infinite conductivity fracture was coupled with the well block. In the case of radial coordinates, water and gas coning studies can be performed.;An automatic time step selector can be used to reduce the time truncation errors as well as reducing the computational costs. The property package is capable of using different techniques like linear interpolation, least squares or cubic splines for predicting fluid properties or the user supplied functions can be used.;The simulator was tested using published data for several options against existing models, and the results were found to be in good agreement.;Initially, partial differential equations describing the fluid flow were approximated using finite difference techniques and the resulting system of equations was solved simultaneously via block alternating direction implicit procedure. The transmissibilities were calculated using explicit, semi-implicit or fully-implicit formulations. Although block centered grids were used in rectangular coordinates, a mesh centered grid was employed in the case of cylindrical-radial coordinate system because of its better representation of the well block pressures. Injected fluids were tracked separately, but they were accounted for within all phases using mixing parameters that empirically predict the incomplete mixing within a block. In the case of polymer injection, the modified Blake-Kozeny equation was used in the representation of the viscoelastic behavior of the injected fluid in the pseudoplastic region. |
