  As a competitive recovery method for heavy oil, In-Situ Combustion (ISC)
shows its great potential accompanied by technological advances in recent
years. Reservoir simulation will play an indispensable role in the prediction
of the implementation of ISC projects. With the computational complexity, it is
imperative to develop an effective and robust parallel in-situ combustion
simulator. In this paper, a mathematical model for In Situ Combustion is
proposed, which takes full consideration for related physical phenomena,
including multi-dimensional multi-component three-phase flow, heat convection
and conduction, chemical reactions, and mass transfer between phases. In the
mathematical model, different governing equations and constraints are involved,
forming a complicated PDE (partial differential equation) system. For physical
and chemical behaviors, some special treatments for the ISC simulator are
discussed and applied. Also, a modified PER (Pseudo-Equilibrium Ratio) method
is proposed in the thesis. A fully implicit scheme is applied, and
discretization is implemented with the FDM (Finite Difference Method). In
solving nonlinear systems, the Newton Method is introduced, and both numerical
and analytical Jacobian matrices are applied. Due to the complexity of an ISC
problem, an appropriate decoupling method must be considered. Thus the
Gauss-Jordan transformation is raised. Then, with certain preconditioners and
iterative solvers, a numerical solution can be obtained. The results of
different models are given, which are validated with the results from CMG
STARS. Also, the scalability of parallelization is proved, indicating the
excellent performance of parallel computing. This accurate, efficient, parallel
ISC simulator applies to complex reservoir models.
