The objective of this study was to develop reaction-kinetics models that can be used to describe the reactions of hydrocarbon fractions at various temperature conditions during the in-situ combustion (ISC) of Athabasca bitumen. In this work, a set of improved kinetic models-including low-temperature-oxidation (LTO), middle-temperature-oxidation (MTO), and high-temperature-oxidation (HTO) reactions-based on saturates, aromatics, resins, and asphaltenes (SARA) fractions in the crude oil are established. These kinetic models are used to reproduce the ramped-temperature-oxidation (RTO) experimental results through numerical simulation.