Oxidation of n-Alkane (n-C8H18) under Reservoir Conditions, in Context of Gas Mixture Injection (CO2/O2): Construction of a Kinetic Model

Abstract

CO2 geosequestration or enhanced oil recovery (EOR) by CO2 injection in hydrocarbon reservoirs is suggested as a short-term solution for limiting CO2 atmospheric accumulation. In the case of oxy-combustion CO2 capture, the main annex gas associated with CO2 is O2 in important proportion (≤7%). Even if hydrocarbon oxidation processes by O2 are well-known in high-temperature–low-pressure (HT-LP) conditions, scarce data are available under reservoir conditions (high-pressure–low-temperature, HP-LT). To predict the hydrocarbon evolution in the presence of O2 in an oil-depleted reservoir, it is necessary to investigate their reactivity. As a matter of fact, a double approach combining experimentation and modeling was performed in this study. Experiments were carried out on a model compound (n-octane), by injecting O2/N2 gas mixtures in a HP-LT titanium reactor. In parallel, a detailed kinetic model for n-octane, generated by the software EXGAS, was applied. Several reactions were added, and some rate parameter...