Crude Oil Oxidation in an Air Injection Based Enhanced Oil Recovery Process: Chemical Reaction Mechanism and Catalysis

Abstract

Air injection as a thermal method for heavy oil recovery has a long history of about a century. However, it has not been widely applied in oilfields to date because of many challenges caused by its technical complexity. In the last two decades, more and more attention has been paid to the air injection technique because of the increasing demand for the effective development of hard-to-recover resources, including heavy oil, bitumen, oil shale, water-flooded mature reservoirs, etc. in a more energy-saving, cost-effective, environmentally friendly way. Consequently, many considerable improvements in both theory and technology have been made recently. This work first reviews the recent advances in the reaction mechanism of crude oil oxidation with highlights on the difference and connection between the oxidation of different oil components as well as their interaction during cocombustion; then, it discusses the catalytic methods for intensifying crude oil combustion with different types of catalysts, including nanometal-based particles, water-soluble metallic salts, and oil-dispersed metal-based catalysts. On the basis of the detailed review and discussion, we shed light on the challenges facing the air injection process and put forward possible methods to solve them. Simultaneously, we point out the neglected aspects of the air injection process and open the way toward fresh thinking for its technical application. And finally, we propose promising perspectives for future work for improving the performance of air injection and its wide application.

Catalytic Oxidation of Alkanes by Organometallics in an In Situ Combustion Process

“…Many efforts have been made to solve these problems. For instance, many initiators have been studied for promoting ignition processes, such as hydroperoxide, linseed, light alkanes, and metal-based catalysts. − …”

“…These catalysts include water-soluble metallic salts, metal nanoparticles, metal oxide nanoparticles, and oil-dispersed organic metal salts. The advantages and disadvantages of these different types of catalysts are compared by Yuan et al…”

“…However, there are a lot of challenges limiting the wide application of ISC. Recently, in a review paper, the progress and challenges in air injectionbased enhanced oil recovery (EOR) techniques are summarized by Yuan et al 2 The difficulty in igniting oils in reservoirs and establishing a self-sustained combustion front is one of the challenges. Many efforts have been made to solve these problems.…”

“…These catalysts include water-soluble metallic salts, metal nanoparticles, metal oxide nanoparticles, and oil-dispersed organic metal salts. The advantages and disadvantages of these different types of catalysts are compared by Yuan et al 2 Considering the merit of oil-dispersed catalysts, we will focus on them in this work. Many works recently have also shown that these oil-dispersed organometallic catalysts exhibited excellent catalytic effects in enhancing the combustion efficiency of crude oils.…”

Evaluation of an Oxygen-Reduced Air Flooding Plugging System and Its Injection Method in the Honghe Oilfield

“…Compared with gas flooding such as carbon dioxide flooding, N 2 flooding, and flue gas flooding, oxygen-reduced air flooding has the advantages of more sources, lower cost, easy availability, and high safety. 24 Oxidation reactions of crude oil at low temperatures generate heat and consume oxygen, resulting in nitrogen flooding and the formation of carbon dioxide that tends to dissolve crude oil. 25 Oxygen-reduced air supplemented with a foam and gel plugging system blocks and seals pore channels, adjusts the matric suction profile, and greatly improves the oil flooding efficiency.…”