Fe3O4/AM-PAA/Ni nanomagnetic spheres: A breakthrough in in-situ catalytic reduction of heavy oil viscosity

Abstract

In-situ catalytic technology for heavy oil reservoirs is widely regarded as one of the most promising methods for heavy oil extraction. However, its large-scale application faces significant challenges due to the lack of efficient stable catalysts, and issues related to the dispersion of catalysts during the injection process. This study introduces a modified nanomagnetic sphere, Fe3O4/AM-PAA/Ni, with catalytic and surface-active properties. With a 1 % mass fraction of Fe3O4/AM-PAA/Ni and 1 % tetrahydronaphthalene (hydrogen donor) at 180°C, heavy oil viscosity dropped by 94.21 %, and asphaltenes and resin reduced by approximately 20 %. Core flooding and alternating magnetic field experiments demonstrated superior dispersion and heating effects for Fe3O4/AM-PAA/Ni nanoparticles compared to traditional Fe3O4. Mechanism analysis revealed that the unpaired electrons and d-orbitals on Fe3O4/AM-PAA/Ni’s transition metals facilitated hydrocarbon chain breakdown and interaction with heteroatoms, while nanoscale nickel enhanced catalytic activity for C-S bond cleavage, further reducing oil viscosity. The amphiphilic polymers on the surface of magnetic nanospheres significantly enhanced the dispersion of the catalyst in heavy oil, increasing the reaction contact area and thereby improving the catalytic performance. This research not only offers vital theoretical insights and practical strategies for efficient heavy oil extraction but also paves the way for advancements in reservoir in-situ modification technologies, showcasing significant application potential and academic value.