In this research, the reaction rates related to an in-situ combustion process were investigated and the effect of heating rate and crude oil type on the reaction rates were investigated. A laboratory model was used to run reaction kinetic experiments in unconsolidated limestone packs using three different crude oils. Experiments were performed under the same pressure and airflow rate and at two different heating rates. It was observed that oxidation of crude oil porous media follows a series of reactions. These reactions can be divided into three regions: low temperature oxidation, fuel deposition, and high temperature oxidation. Produced gas analysis was used to determine the activation energy of the samples. Experiments were also performed with thermogravimetry (TG/DTG), and the results are discussed.