Changes in hydrocarbon content of heavy oil during hydrothermal process with nickel, cobalt, and iron carboxylates

We conducted autoclave modeling experiments to study the process of upgrading heavy oil in the reservoir conditions and used carboxylates of transition metals (Ni, Co, Fe) as catalyst precursors. The process was carried out at temperatures of 250, 300, and 350 °C in the presence of a naphthenoaromatic hydrogen donor. We found that significant content changes of oil occur at temperatures of 300 and 350 °C accompanied by an increase of light fractions and a decrease of high molecular weight hydrocarbons. We studied the hydrocarbon composition of the initial oil and the products of the hydrothermal process as well as tetralin (proton donor) transformations to determine the patterns of influence of the process conditions and catalyst precursors.