| Abstract |
It has long been recognized that a common ground exists between governing equations used for describing various flow and transport phenomena in porous media. Put another way they are all generally based on the same form of mass and/or energy conservation laws. This implies that there may exist a unified formulation and numerical scheme applicable to modeling all of these physical processes. This paper explores such a possibility and proposes a generalized framework, as well as a mathematical formulation for modeling all known transport phenomena in porous media. Based on this framework, a unified numerical approach is developed and tested using multidimensional, multiphase flow, isothermal and nonisothermal reservoir simulators. In this approach, a spatial domain of interest is discretized with an unstructured grid, then a time discretization is carried out with a backward, first-order, finite-difference method. The final discrete nonlinear equations are handled fully implicitly, using Newton iteration. In addition, the fracture medium is handled using a general dual-continuum concept with continuum or discrete modeling methods. A number of applications are discussed to demonstrate that with this unified approach, modeling a particular porous-medium flow and transport process simply becomes a matter of defining a set of state variables, along with their interrelations or mutual influence. |
