EFFECT OF INTERSTITIAL WATER SATURATION AND AIR FLUX ON COMBUSTION KINETICS OF HIGH PRESSURE AIR INJECTION (HPAI)

High Pressure Air Injection (HPAI) in deep light oil reservoirs has received notable attention in the last three decades after its first successful field application in 1979. Kinetics of the oxidation reactions associated with HPAI are known to be the most crucial mechanism which control the overall performance of air injection processes; however, they are not fully explored for light oils yet. This paper describes the results of an experimental study conducted to characterize some main parameters which impact the reaction kinetics of light oil oxidation/combustion in HPAI. Vaporization of oil has been reported in the literature as a mechanism associated with kinetics of air injection processes; however, the parameters controlling the vapor phase oxidation/combustion have not been included in the studies of oxidation kinetics. Interstitial water saturation plays an important role on heat transfer and consequently the reaction kinetics. However, there is no reported data in literature investigating this factor. This study aims to shed light on these unknown aspects of light oil air injection (HPAI). Several oxygen and nitrogen injection experiments have been performed on recombined light oil and also a pure oil component sample in a 45cm long, ramped temperature oxidation reactor. Experiments were run in presence and absence of interstitial water at two different levels of injection flux. Chromatographic analysis of the product gas stream, simulated distillation of the produced oil and determination of the mass of solid residue on the post‑test core were performed for each experiment. An endothermic vaporization front was observed to precede the thermal front in low flux air injection tests. Interstitial water saturation had a major impact on formation and extent of endothermic vaporization front. The tests which were run on recombined samples with no water barely developed a distinct distillation wave.