Siberian Federal University

The study explored the composition and structure of transforming highly viscous oil under hydrothermal conditions, formed in situ from a nickel-based oil-soluble precursor. Notably, the catalyst significantly facilitates the breakdown of resins and asphaltenes. Specifically, experiments were conducted using oil-soluble nickel carboxylates and a hydrogen donor. Consequently, it was found that employing the catalyst precursor alters the gas composition of aquathermolysis products, rheological properties, and component composition. Moreover, when a nickel-based catalyst is utilized at 200 °C for 24 hours, the viscosity is reduced by 1.5 times compared to the control experiment. Additionally, the decomposition of the catalyst precursor results in the formation of nanometer- sized catalyst particles, as confirmed by scanning electron microscopy data. Thus, these particles do not clog the porous medium of the oil- saturated reservoir rock, allowing oil from other layers to be involved in the upgrading process