Reactivity of hydrocarbons in response to injection of a CO2/O2 mixture under depleted reservoir conditions : experimental and numerical modeling

Le stockage géologique du CO2 et/ou la récupération assistée de pétrole par injection de CO2 dans des réservoirs pétroliers, pourraient permettre de limiter le CO2 atmosphérique. Cependant, le CO2 peut être associé à de l’oxygène. Prédire l’évolution des hydrocarbures dans ces conditions, implique d’étudier les mécanismes de l’oxydation. Des expériences d’oxydation et des modélisations cinétiques détaillées ont été réalisées avec des composés modèles purs ou en mélange. La comparaison des résultats expérimentaux et de modélisation a permis la construction d’un mécanisme d’oxydation d’hydrocarbures, et a souligné les paramètres influençant l’apparition d’une auto-inflammation. La bonne cohérence des expérimentations et des modélisations, est prometteuse pour le développement d’un outil de prédiction afin de déterminer la limite d’auto-inflammation ainsi que l’évolution de la composition des hydrocarbures, pour estimer la stabilité d’un système pétrolier en contexte d’injection de CO2The geological storage of CO2 (CO2 Capture-Storage – CCS) and the Enhanced Oil Recovery (EOR) by CO2 injection into petroleum reservoirs could limit CO2 atmospheric accumulation. However, CO2 can be associated with oxygen. To predict the hydrocarbon evolution under these conditions involves the study of oxidation mechanisms. Oxidation experiment and kinetic detailed modeling were carried out with pure compounds. The comparison between experimental and modeling results led to the construction of a hydrocarbon oxidation kinetic model and emphasized the parameters leading to auto ignition. The good agreement between our experiments and modeling are promising for the development of a tool predicting the critical temperature leading to auto-ignition and the evolution of hydrocarbon composition, to estimate the stability of a petroleum system in CO2 injection contex

Réactivité des hydrocarbures en réponse à une injection de CO2/O2 dans des conditions de réservoirs pétroliers déplétés: modélisations expérimentale et numérique

The geological storage of CO2 (CO2 Capture-Storage – CCS) and the Enhanced Oil Recovery (EOR) by CO2 injection into petroleum reservoirs could limit CO2 atmospheric accumulation. However, CO2 can be associated with oxygen. To predict the hydrocarbon evolution under these conditions involves the study of oxidation mechanisms. Oxidation experiment and kinetic detailed modeling were carried out with pure compounds. The comparison between experimental and modeling results led to the construction of a hydrocarbon oxidation kinetic model and emphasized the parameters leading to auto ignition. The good agreement between our experiments and modeling are promising for the development of a tool predicting the critical temperature leading to auto-ignition and the evolution of hydrocarbon composition, to estimate the stability of a petroleum system in CO2 injection contextLe stockage géologique du CO2 et/ou la récupération assistée de pétrole par injection de CO2 dans des réservoirs pétroliers, pourraient permettre de limiter le CO2 atmosphérique. Cependant, le CO2 peut être associé à de l’oxygène. Prédire l’évolution des hydrocarbures dans ces conditions, implique d’étudier les mécanismes de l’oxydation. Des expériences d’oxydation et des modélisations cinétiques détaillées ont été réalisées avec des composés modèles purs ou en mélange. La comparaison des résultats expérimentaux et de modélisation a permis la construction d’un mécanisme d’oxydation d’hydrocarbures, et a souligné les paramètres influençant l’apparition d’une auto-inflammation. La bonne cohérence des expérimentations et des modélisations, est prometteuse pour le développement d’un outil de prédiction afin de déterminer la limite d’auto-inflammation ainsi que l’évolution de la composition des hydrocarbures, pour estimer la stabilité d’un système pétrolier en contexte d’injection de CO

Oxidation of N-hexadecane and crude oil in response to injection of a CO2/O2 mixture under depleted reservoir conditions: Experimental and kinetic modeling preliminary results

International audienceCO2 capture and storage in hydrocarbon reservoir seems to be a good solution to reduce greenhouse gas emissions. However, combustion residual gases are not only composed of CO2 but also associated with minor gases. In the case of oxy-combustion, the main minor gas is oxygen in elevated proportion (up to 7%). O-2 injection can induce hydrocarbon oxidations and hence it is necessary to evaluate its consequences on the storage. Hydrocarbon oxidations were studied with a double approach: experiments and kinetic modeling. In a first step, pyrolysis of a model hydrocarbon (n-hexadecane) in CO2 atmosphere reveals no chemical reactivity between hydrocarbons and CO2. Experimental oxidations were then carried out by injecting artificial air in a closed reactor on: (i) a pure n-alkane (n-hexadecane) and (ii) a natural crude oil. Results of both experimental and numerical modeling showed two oxidation types depending on temperature: a low oxidation, and an auto-ignition. The simulation results were globally in agreement with experiments but need to be adapted to low temperature-high pressure conditions. The preliminary findings of this investigation emphasize on the oxidation consequences: (i) on oil composition and (ii) risk (auto-ignition) in context of gas mixture injection (CO2/O-2) in petroleum system

Oxidation of n -Alkane ( n -C 8 H 18 ) under Reservoir Conditions in Response to Gas Mixture Injection (CO 2 /O 2 ): Understanding Oxygenated Compound Distribution

International audienc

Flue gas injection into depleted tight hydrocarbon reservoirs in the context of global warming mitigation: Computed evolution of some reservoir parameters

International audienc

Oxidation of n-Alkane (n-C8H18) under Reservoir Conditions, in Context of Gas Mixture Injection (CO2/O-2): Construction of a Kinetic Model

International audienceCO2 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 O-2 in important proportion (=7%). Even if hydrocarbon oxidation processes by O-2 are well-known in high-temperaturelow-pressure (HT-LP) conditions, scarce data are available under reservoir conditions (high-pressurelow-temperature, HP-LT). To predict the hydrocarbon evolution in the presence of O-2 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 O-2/N-2 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 parameters have been adjusted to adapt the model to reservoir conditions. The modified model was validated by experiments performed at different reaction temperatures and O-2 concentrations. The consistency between experimentations and modified oxidation model is promising for the development of a tool allowing the prediction of hydrocarbon reservoir stability

Oxidation of <i>n</i>‑Alkane (<i>n</i>‑C₈H₁₈) under Reservoir Conditions in Response to Gas Mixture Injection (CO₂/O₂): Understanding Oxygenated Compound Distribution

CO₂ geosequestration [carbon capture and storage (CCS)] and enhanced oil recovery (EOR) by CO₂ injection in hydrocarbon-depleted reservoirs could limit the CO₂ atmospheric accumulation. In the case of CO₂ capture by oxy-combustion, the main annex gas associated with CO₂ is O₂. O₂ that remains in the flue gas for injection can induce the oxidation of the hydrocarbons contained in the reservoirs. The effect of O₂ must be studied in terms of benefit and/or risk for CCS or EOR. To investigate the mechanism of hydrocarbon oxidation, it is essential to analyze the distributions of the formed oxygenated compounds. That is why experiments have been performed with a model compound (<i>n</i>-octane) in a closed reactor under high pressure at different temperatures and with different oxygen concentrations. The product distribution suggests two pathways of <i>n</i>-alkane oxidation, with (i) the preservation of the aliphatic chain length of the initial <i>n</i>-alkane, which generates oxygenated products with the same number of carbon, and (ii) the breakdown processes of the initial <i>n</i>-alkane, which generates low-molecular-weight oxygenated products. The new understanding of the mechanism of <i>n</i>-alkane oxidation could be incorporated into the detailed kinetic model of our previous study, which is specific to the reservoir conditions