In situ combustion is a method with a large potential for recovery of heavy oil reserves, worse yet has many complexities that make it difficult its field scale development. One of these difficulties is precisely understand the different kinds of reactions taking place once the process starts. One tool that helps the engineer to understand what is happening during the process is the numerical simulation and specifically, for the case of combustion, the kinetic model. This model has two essential parts: the reactions and kinetic parameters. The reactions are developed based on the pseudocomponents used to characterize the fluid and the kinetic parameters were obtained from measurements made in the laboratory tests: Ramped temperature oxidation (RTO) and Accelerating Rate Calorimeter (ARC). The initial characterization of a fluid throws several components, which are subsequently lumped to the least amount possible without losing crude representation. These pseudocomponents must correctly represent the PVT behavior of oil. This matching to the actual behavior is achieved using suitable software. Based on the set of tests, it stars to match the behavior of the main fluid properties, for this, have previously chosen the most relevant parameters that may require matching to obtain a more representative model. Within the main tuning parameters are the critical properties of the fluid, accentric factors, lumping and splitting schemes and viscosity coefficients.
This paper proposes a scheme that helps to build a model that represents the phase behavior when the fluid is subjected to various conditions during the development of the combustion process. Matched the fluid model, this can be used in different scale models: CTO(Combustion Tube Tests), RTO or field. In this case, the successful development of the reactions involved in the kinetic model for in situ combustion process is linked the phase behavior model and the molecular weight of the pseudocomponents.