In situ combustion of light oil (37 degrees API) was studied here through combustion tube experiment and mathematical modeling. The flue gas at the effluent provided a reaction stoichiometry, and indicated an aggregate molecular entity similar to bitumen as the burning fraction of the crude oil. A mathematical model based on 1D heat and mass transport with three phases in porous media effectively simulated the sustenance and progression of the combustion front, observed experimentally. The sensitivity of these aspects to the perturbations in rate constants, activation energy, and heat of reaction is discussed here. The extent of accumulation of oil and water at the downstream side of the combustion front was evaluated. The simulation results concerning cumulative collection of oil at the effluent was verified with experimental data. The width of the combustion zone, evident from the concentration profile of oxygen, is discussed in this article.