Injection of an oxygen-containing gas into a light-oil reservoir: Numercial evaluation of oil oxidation and ignition phenomena

CO2 or methane injection is a recovery process often used for a large variety of reservoirs. Economical considerations should lead to inject a cheaper gas, generally air or nitrogen with a poor oxygen content. Under severe conditions of pressure and temperature (e.g. typical North Sea light-oil reservoir), one of the main risks related to th is last process is the oil oxidation leading to chemical degradation and even spontaneous ignition. It is therefore a prime necessity to determine accurately the oil oxidation rate, the delay of a possible ignition and the extension of the oxidation zone, which strongly depend on eperating conditions, reservoir characteristics and oil oxidability (mainly pressure, temperature and reaction kinetic parameters).