Although coke combustion studies have long been conducted, the literature is still lacking an accurate understanding of reaction kinetics. To this end, the thermo-oxidative behaviours of Neilburg oil and its asphaltene fraction were examined in the presence of core sand. Thermogravimetric analysis (TGA) was performed in a flowing atmosphere at the heating rate of 10 degrees C/min up to 750 degrees C. Both nitrogen and air were used at a flow rate of 45 ml/min in the experiments. As earlier researchers have observed, at least two main regions of reactions were identified by the thermogravimetric (TG) and derivative thermogravimetric (DTG) thermograms. Various effects, including distillation, low-temperature oxidation (LTO), thermal cracking, middle-temperature oxidation (MTO), high-temperature oxidation (HTO) or combustion, and even mineral decomposition, were observed. In this study, Neilburg oil and asphaltenes were completely cracked in a nitrogen atmosphere at 425 degrees C to produce coke. Subsequently, the fresh coke was subjected to isothermal combustion at several, temperatures from 374 degrees C to 519 degrees C. A two-step oxidation reaction model was applied to describe this combustion process. The chemical reactions were simplified into two oxidations occurring in series. In the first reaction, coke was partially oxidized to form an intermediate product, which was then burned in the second reaction. Based on the TGA data, kinetic parameters were estimated with the aid of custom written software. For comparison, the one-step oxidation reaction model was also employed to predict the combustion process. The two-step oxidation reaction model gave a better fit to the experimental data. It was also confirmed that the coke derived from the Neilburg asphaltenes is reasonably representative of the coke derived from the whole oil.