Abstract
<jats:title>Abstract</jats:title> <jats:p>Reliable performance prediction is essential for the successful design and implementation of enhanced oil recovery processes. In situ combustion (ISC) remains particularly challenging to model due to the complex coupling of heat transfer, multiphase flow, and chemical reaction kinetics. This complexity limits the accuracy of existing numerical and analytical models used to evaluate air-injection-based recovery techniques. A critical challenge in ISC modeling lies in defining appropriate kinetic reaction models that accurately represent compositional changes and heat generation during combustion. Despite extensive research reported in the literature, significant uncertainty remains regarding the kinetics of combustion reactions in ISC processes. Conventional models generally assume that oil undergoes low-temperature oxidation and pyrolysis prior to burning, with solid coke acting as the primary fuel for high-temperature oxidation reactions. However, experimental evidence suggests that this assumption alone cannot explain the sharp temperature peaks observed in combustion tube experiments.</jats:p> <jats:p>Motivated by this discrepancy, a novel thick-walled cylindrical plug-flow reactor was designed to investigate vapor-phase combustion in porous media. The experimental setup consisted of both clean non-saturated sand and oil/water-saturated sand sections, with controlled linear heating and localized ignition. Experimental results demonstrate that under favorable conditions, a distinct temperature response develops in the non-saturated region, sustained by combustible hydrocarbon vapors generated through distillation and chemical reactions in the saturated zone. Recognition of vapor-phase combustion in porous media provides a missing element in ISC kinetic models and offers a pathway to improve the accuracy of thermal simulations and performance prediction for laboratory and field-scale air-injection projects.</jats:p>