In order to evaluate the efficiency of the catalytic aquathermolysis process, physical modeling was carried out on bituminous sediments of Paleocene–Miocene carbonate rocks, characterized by the presence of open and closed fractures. In this context, three filtration experiments were performed on an unextracted reservoir model with extra-viscous oil (EVO). Prior to the experiments, the mineral composition of the rock was determined by X-ray diffraction analysis (XRD) and the content of organic matter and coking products was determined before and after the experiment by thermogravimetric analysis (TGA) as well as the group composition of oil (SARA) before and after the experiment by nuclear magnetic resonance (NMR), gas composition at the fluid separation line, and oil displacement coefficient (ODC). The results of the conducted experiments show that the efficiency of displacement of extraviscous oil could be significantly increased by the use of a solvent and the combined use of a solvent and a catalyst (+9.3% and +17.1% of the oil displacement coefficient, respectively), which is associated with the processes of oil refining.

This paper examines the transformation of heavy oil composition in porous media of carbonate reservoir rocks under hydrothermal processes in the presence of transition metal sulfides, which form in-situ from the organic-soluble precursors. It was revealed that catalysts significantly promoted the destruction of asphaltenes. Its content was reduced from 15 wt.% to 12 wt.% in the presence of iron-based catalyst. The bimetallic catalyst based on nickel and iron with the mass ratio of 1:1 exhibited the best performance in terms of reducing heavy oil viscosity. Combination of two different metals allowed to involve the wide ranges of carbon-heteroatom bonds, which are mainly concentrated in resins and asphaltenes, into the hydrogenolysis reactions. Irreversible reduction of heavy oil viscosity in-place not only eases the further downstream processes such as pipeline transportation and refinery, but also decreases carbon footprints of the produced oil owing to the increase in the intensity of hydrogenation processes.

An exhaustive review on the application of different metal-based nanoparticles for the upgrading of heavy oils has been performed. Particular emphasis has been put on those catalysts used for in-situ upgrading using various thermal treatment methods aiming at extracting heavy oils in a more effective manner. Different types of catalysts have been identified, such as monometallic (Mg, Al, Si, Ca, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Zr, Mo, Ce, and W), non-supported bimetallic (Ti/Zr), non-supported polymetallic (various mixtures of Co, Mo, Ni, W, Al, Zn, Cu), and supported (various metals on silica, alumina, carbon, zeolite, biogenic particles, complex inorganic and organic). Due to the great diversity of nanoparticulated catalysts (type, metal content, synthesis procedure, particle size) and evaluation conditions (experimental setup, reaction conditions, type of feed), it is not possible to make a direct comparison on their performance. Some results are highlighted on the effectiveness of the catalysts for heavy oil upgrading in terms of asphaltene adsorption, viscosity reduction, increase of API gravity, and coke formation. The reviewed literature indicates the need for more research on this topic as to develop more effective catalysts not only for increasing the recovery factor but also for permanent upgrading of the quality of heavy and extra-heavy oil.