This research is aimed at providing a better understanding of the oxidation behaviour of fractions of crude oil, and to then develop an approach to improve ignition for air injection processes. In this research, Thermogravimetric and Differential Thermal Analysis (TG/DTA) techniques were used to investigate oxidation behaviour using thermal fingerprinting effects on pure paraffin samples and mixtures of pure components with crude oil. The results demonstrated that each paraffin sample shows different oxidation behaviours at low temperatures and high temperatures. The fractions lighter than C16 distill before they reach a temperature where oxidation reactions are significant. Only low temperature exothermic activities are apparent for the fractions between C 16 and C26. The heavier fractions show both low and high temperature exothermic activities. The lower molecular weight samples show lower onset temperatures for oxidation reactions. With increasing molecular weight, the exothermic peak temperatures both in the low and high temperature regions shift to higher temperatures and increased energy release. When low activity Oil B and the more reactive Oil C were mixed with a small amount of paraffin sample heavier than C26, both crude oils showed intensified low temperature oxidation behaviour, with a greater magnitude of heat evolution. The addition of heavier paraffins offers the potential to accelerate reactions and improve ignition.