Enhancing Thermal Recovery of Heavy Oil by In Situ Combustion: The Role of Micro and Nanostructured Manganese Oxide Catalysts

Heavy oil reserves are recognized as being a significant yet challenging energy resource due to high viscosities. It is common knowledge that thermal recovery methods like in situ combustion rely on fuel deposition and oxidation to enhance oil mobility. This study explored micro and nanostructured manganese oxide catalysts to improve the efficiency of heavy oil oxidation. MnO composites were synthesized and characterized by X-ray powder diffraction (XRD), Scanning Electron Microscopy (SEM), Energy-dispersive X-ray (EDX), Thermogravimetric analysis (TGA), and N2 physisorption. It has been found that the smaller nanoparticles showed higher surface area (38 m2/g), oleic acid content, and mesoporosity compared to the larger microparticles which exhibited a surface area of 12.85 m2/g. Moreover, differential scanning calorimetry (DSC) analysis confirmed the catalytic activity of both particle types by intensifying oxidation peaks and lowering activation energies. However, the isoconversional calculations revealed minimal difference in oxidation times between MnO micro and nanoparticles at various conversion rates. To overcome aggregation issues, MnO nanoparticles were incorporated onto SiO2 nanospherical particles. As a result, MnO/SiO2 composites exhibited increased surface area and pore volume. Most importantly, they demonstrated significantly enhanced heavy oil oxidation rates, especially at a high temperature oxidation region which is considered the main key of a successful application of in situ combustion. This work highlights the promise of nanostructured MnO catalysts to improve the efficiency and economics of thermal heavy oil recovery. Further optimization of parameters like size, morphology, and dispersion extent within the reservoir could enable these materials to stabilize the combustion front and maximize heavy oil production.