NonArrhenius kinetics for reactive transport simulations of in situ combustion

Abstract

In situ combustion (ISC) is a substantially exothermic reactive transport process. Due to the multicomponent nature of crude oil, ISC reactions are time consuming to characterize and represent accurately in a compact mathematical form. We have developed a methodology for simulation of thermal reactive flow with fidelity to reaction kinetics without construction of a model for reaction. The progress of ISC reactions is represented in a three-dimensional space bounded by conversion (extent of reaction), temperature, and heating rate that may be obtained experimentally. The representation may be either in continuous or tabular form (preferred). The reaction model free approach as applied to ISC is outlined and demonstrated for the first time. Comparison to the predictions of ISC from a conventional simulator is favorable. The results of the reaction-model free method match the common reaction model approach for one and two dimensional combustion processes. The reaction model free approach simplifies the numerical representation of reactive transport. The approach covers the whole range of heating rates that exist in combustion processes and it is as accurate as current methods.