A new multidimensional three-phase flow simulator has been developed to simulate the in-situ combustion process. This simulator is written in order to study the effect of the main parameters thought to influence the performance of this process and to provide the academic community with a comprehensive, robust, efficient, and easy to modify program. It is not intended to compete with the more general commercial simulators available for the oil industry. The model uses four reactions and six components. Heat transport is assumed to take place by convection and conduction. The effects of gravity, capillary pressure, and heat losses to surrounding strata are also included. The oil is represented by two of the components termed the light and heavy pseudocomponents. The simulator has been validated by comparing the results with results of similar calculations taken from a more general and well-tested model. A series of studies were performed in order to test the robustness of the program to the changes in the input parameters and also to understand the influence of each input parameter on the characteristic performance of the process. The results of an investigation of the sensitivity to the kinetic parameters (activation energy and pre-exponential factor) are presented in this paper.