Influence of the composition of oxygen–carbon dioxide gas mixture on the oxidation process of heavy crude oils

Abstract

© 2019, International Multidisciplinary Scientific Geoconference. All rights reserved. In-situ combustion is considered as one of the most effective ways to enhance recovery of heavy crude oils and bitumens. The oxygen from injected air reacts with the heavy components of the crude oil, forming a hot zone in which the cracking and oxidation of the heavy fractions occurs. It is noted that the combustion process essentially depends on the pressure and the nature of the crude oil. The effect of the oxygen content in the gas mixture on the combustion front propagation of heavy crude oils is shown. When the oxygen content reached 90%, the combustion front reaches its maximum. It is noted that an increase of an air pressure leads to a significant expansion of the combustion front. An analysis of the influence of composition and the nature of the components in the gas mixture on the thermodynamic and kinetic parameters of combustion has not been studied before. In this paper, we analyze how the ratio of the components of the oxygen–carbon dioxide gas mixture affects on thermodynamic, kinetic parameters of crude oil oxidation at reservoir temperature and pressure. Also we studied the influence of the gas mixture composition on the rheological parameters of crude oil. Accelerating rate calorimetry and a high-pressure rheometery were used as the main methods. Kinetic parameters (activation energy, reaction rate, etc.) of heavy crude oil oxidation processes were obtained. The most effective gas mixtures for possible use in real deposits were determined. It was found that with an increase in the oxygen content in the gas mixture, the activation energy changes significantly. An effect of the second component (carbon dioxide and nitrogen) on the oxidation process in gas mixtures has been analyzed.